Key Facts
- Hangul: 확실하다 (hwaksilhada)
- Meaning: certain
- Part of speech: adjective (형용사)
- Level: B1
- Stem: 확실하
- Class: 하다 type
- Dictionary-form sound: [확씰하다]
What Does 확실하다 Mean?
확실하다 says that you can rely on something. 확실한 정보 is reliable information, and 시간이 확실해요? asks whether the time is fixed. The subject takes 이/가 or 은/는, and it often follows a -는지 clause in the negative, as in 맞는지 확실하지 않아요 ("I am not sure whether it is right"). In daily talk, 확실하지 않아요 is the polite way to admit that you are not sure.
How Do You Pronounce 확실하다?
The dictionary form is said [확씰하다]: the ㄱ of 확 makes the ㅅ that follows tense, so you hear ㅆ. The same tensing shows in the polite present 확실해요, read [확씰해요]. The formal 확실합니다 is [확씰함니다], and the past 확실했어요 is [확씰해써요].
How Do You Use 확실하다 in a Sentence?
시간이 확실해요?
Is the time certain?
시간이 is the thing in question, and the rising question asks if it is fixed. The polite present works here.
확실한 답을 알고 싶어요.
I want to know a definite answer.
The modifier 확실한 sits before 답을, and 알고 싶어요 says that you want to know. The combination asks for something solid.
확실하면 말해 주세요.
If you're sure, please tell me.
The conditional 확실하면 means "if you're sure", and 말해 주세요 asks for the answer.
Usage Notes for 확실하다
The word is frequent at work and in daily talk. Softening a claim with 확실하지 않아요 is polite and honest. The adverb 확실히 means "certainly" and goes before verbs. If you are checking facts and figures, 정확하다 is more exact, while 분명하다 stresses clarity. Use 확실하다 for a sureness that rests on trust or a decision.
How Does Hwaksilhada Conjugation Work?
확실하다
| Form | Korean | Romanization | Rule |
|---|---|---|---|
| Polite present | 확실해요 | ||
| Polite past | 확실했어요 | ||
| Polite future (plan) | 확실할 거예요 | ||
| Polite future (intention or guess) | 확실하겠어요 | ||
| Formal present | 확실합니다 | ||
| Formal past | 확실했습니다 | ||
| Formal future | 확실할 것입니다 | ||
| Casual present | 확실해 | ||
| Casual past | 확실했어 | ||
| Casual future | 확실할 거야 | ||
| Because / and then | 확실해서 | ||
| Conditional (if) | 확실하면 | ||
| Present modifier (before a noun) | 확실한 | ||
| Past modifier (before a noun) | 확실했던 | ||
| Future modifier (before a noun) | 확실할 | ||
| Negative with 안 (short) | 안 확실해요 | ||
| Negative (long form) | 확실하지 않아요 |
| Form | Korean | Sound if different |
|---|---|---|
| Polite present | 확실해요 | [확씰해요] |
| Polite past | 확실했어요 | [확씰해써요] |
| Polite future (plan) | 확실할 거예요 | [확씰할꺼예요] |
| Polite future (guess) | 확실하겠어요 | [확씰하게써요] |
| Formal present | 확실합니다 | [확씰함니다] |
| Formal past | 확실했습니다 | [확씰핻씀니다] |
| Formal future | 확실할 것입니다 | [확씰할꺼심니다] |
| Casual present | 확실해 | [확씰해] |
| Casual past | 확실했어 | [확씰해써] |
| Casual future | 확실할 거야 | [확씰할꺼야] |
| Because / and then | 확실해서 | [확씰해서] |
| Conditional (if) | 확실하면 | [확씰하면] |
| Modifier, present | 확실한 | [확씰한] |
| Modifier, past | 확실했던 | [확씰핻떤] |
| Modifier, future | 확실할 | [확씰할] |
| Short negative | 안 확실해요 | [안 확씰해요] |
| Long negative | 확실하지 않아요 | [확씰하지 아나요] |
Is 확실하다 Regular or Irregular?
확실하다 follows the standard 하다 pattern. The stem 확실하 uses 해 before 아 or 어: 확실해요, 확실해서 and 확실했어요. Before a consonant ending the 하 stays, giving 확실합니다, 확실하면 and 확실하지 않아요. The sound changes inside 확실 happen only in speech. For more words built this way, see the lesson on how 하다 becomes 해요.
Common Mistake with 확실하다
Wrong: ✗ 확실이 해요
Correct: ✓ 확실해요
Why: 확실 is not used as a noun with 이 plus 해요. The adjective conjugates directly, and the adverb is 확실히.
확실하다 Versus 정확하다 and 분명하다
| Word | How it differs |
|---|---|
| 정확하다 | 정확하다 is accurate, exact and matching the facts. 확실하다 is certain or firmly decided. |
| 분명하다 | 분명하다 is clear and unmistakable. 확실하다 is sure, without doubt. |
Confirming the Time of a Meeting
Two colleagues are checking whether a meeting time has been settled. One person has an older message but needs a definite answer before making arrangements.
Jisu
회의 시간이 확실해요?
Hoeui sigani hwaksilhaeyo?
Is the meeting time definite?
Alex
아직 확실하지 않아요.
Ajik hwaksilhaji anayo.
It is not certain yet.
Jisu
확실하면 알려 주세요.
Hwaksilhamyeon allyeo juseyo.
Please let me know when you are sure.
Alex
네. 확인하고 연락할게요.
Ne. Hwaginhago yeollakalgeyo.
Yes. I will check and get in touch.
확실해요 asks about the status of the time. 아직 확실하지 않아요 leaves the decision open: “not certain yet”. 확실하면 sets a condition for the follow-up message. In this situation, English “when you are sure” sounds natural even though the Korean conditional can also be translated “if”.
Useful Combinations with Certainty
확실한 정보 is reliable or definite information. 확실한 증거 is firm evidence. Both put 확실한 before a noun and describe how securely you can rely on it. The claim is stronger than merely saying that someone has heard a rumour. If you are only repeating an unconfirmed message, the negative 확실하지 않아요 better expresses that limit.
확실한 답 means a definite answer. Someone asking for one usually wants the uncertainty resolved: whether a reservation is accepted, whether a time is fixed, or whether a decision has been made. The existing sentence 확실한 답을 알고 싶어요 therefore asks for more than any answer at all.
확실히 is an adverb. In 확실히 알다, “to know for sure”, it describes the knowing. In 확실히 다르다, “to be definitely different”, it strengthens the description of a difference. Its final 히 is part of the spelling. The adjective 확실하다 and the adverb 확실히 do different jobs even though both concern certainty.
Does 확실해요? Sound Polite or Doubtful?
확실해요? can be a neutral request for confirmation when two people are checking plans. After someone has already answered confidently, repeating the same question can sound as though you doubt them. The 요 ending supplies politeness to the listener, but the timing, repetition, and tone still shape the message.
정말 확실해요? adds “really”: “Are you really sure?” This is useful when a mistake would affect plans, such as booking transport for a meeting. It also makes the challenge stronger. In a routine conversation, a single confirmation question is often enough once the other person has checked the information.
확실하지 않아요 and 잘 모르겠어요 both allow uncertainty, but they point to different limits. The first says the matter is not certain; the second says the speaker does not know well or cannot say. You might have a likely answer and still say 확실하지 않아요 because you have not confirmed it.
Where Does 확실하다 Appear?
In workplace messages, 확실한 answers and information help people decide what to do next. A manager may need a confirmed time before telling a client. In news or discussions of an incident, 확실한 증거 concerns evidence rather than a person's confidence alone. The noun after 확실한 tells you what is being presented as certain.
In drama dialogue, a short 확실해? can sound urgent or suspicious. It is the casual counterpart of 확실해요?, suitable between close speakers or in an established casual relationship. The word also works in calm factual explanations, so it does not automatically signal an argument.
Words for Checking Information
| Korean | Meaning | Useful note |
|---|---|---|
| 확인하다 | to check / confirm | The action used to resolve uncertainty in the dialogue. |
| 정보 | information | Common after 확실한 when discussing reliability. |
| 증거 | evidence | Common after 확실한 when supporting a claim. |
| 정확하다 | to be accurate | Describes matching the facts or the correct figures. |
For vocabulary around meetings and messages, see the office vocabulary lesson.
Keep 하다 and 히 Separate in Your Thinking
The 하다 ending in 확실하다 belongs to an adjective: it describes certainty. It does not mean the speaker is performing an action called “certainty”. This is why the present modifier is 확실한, as in 확실한 답. A word ending in 하다 can be descriptive even when many other 하다 words name actions.
The adverb 확실히 needs something to describe, such as 알다. The complete statement 확실해요 already supplies the description “is certain”. Adding a space inside 확실해요 or replacing 해요 with 히 changes the grammatical structure, rather than making the same sentence more formal.
Mini Drill: Choose the Right Form
- Give the polite present of 확실하다.
- Complete “a definite answer”: ____ 답.
- Say “It is not certain” with the long negative.
- Choose the adverb spelling: 확실히 or 확실이.
Show drill answers
- 확실해요. 하다 contracts to 해요.
- 확실한 답.
- 확실하지 않아요. Write 않아요 as a separate word.
- 확실히. It can describe knowing or checking something.
Quick Self-Test
- Does 확실한 증거 mean firm evidence or a fixed meeting time?
- Can a repeated 확실해요? express doubt despite 요?
- Which word names the act of checking: 확인하다 or 확실하다?
Show answers
- Firm evidence. 증거 means evidence.
- Yes. Context and tone can make it a challenge.
- 확인하다. 확실하다 describes being certain.
Frequently Asked Questions
How Do I Say I'm Not Sure?
Say 확실하지 않아요, said [확씰하지 아나요].
How Do I Ask If Someone Is Certain?
Say 확실해요? with a rising tone, as in 시간이 확실해요?
What Is the Adverb?
The adverb is 확실히, meaning certainly.
Can I Say 확실이 해요?
No. Use 확실해요, since the adjective conjugates directly.
Which Words Are Related to 확실하다?
What Should You Learn Next?
Study 정확하다 next for accuracy, then 분명하다 for clarity, and 당연하다 for what is expected. Try the Korean verb conjugator on a similar stem, then look up its entry in the Korean verb dictionary.