DOUBT & CERTAINTY IN KOREAN
In conversations, we often need to show confidence or doubt about certain facts or situations.
Korean has specific structures that convey these nuances effectively.
This lesson will cover phrases to express certainty with confidence or convey doubt with reservation.

ABSOLUTE CERTAINTY
This structure is used to express absolute certainty, similar to “There’s no doubt that…” or “It must be…”.
It is used to express confidence or certainty, often in contexts where the speaker is convinced of a fact or outcome.
PATTERN
S + V + -에 틀림없다
그가 범인인 게 틀림없어요. | There’s no doubt he’s the culprit. |
이 제품이 제일 좋은 게 틀림없습니다. | There’s no doubt this product is the best. |
저 사람은 한국 사람인 게 틀림없어요. | That person must be Korean. |
View More Examples:
이 음식이 정말 맛있는 게 틀림없어. | This food must be really delicious. |
그들이 성공할 게 틀림없어요. | There’s no doubt they will succeed. |
오늘 회의가 길어질 게 틀림없어요. | There’s no doubt today’s meeting will be long. |
STRONG DOUBT
This sentence structure expresses strong doubt, often translated as “It can’t be…” or “It’s impossible that…”.
It strongly conveys disbelief or doubt, often implying that something is too unlikely or implausible to be true.
PATTERN
S + V + -ㄹ/을 리가 없다
그가 그럴 리가 없어요. | It’s impossible that he would do that. |
이렇게 비싼 게 사실일 리가 없어요. | It can’t be true that it’s this expensive. |
아직도 자고 있을 리가 없어요. | It’s impossible that he’s still sleeping. |
View More Examples:
그렇게 빨리 끝났을 리가 없어. | There’s no way it ended that quickly. |
내가 모를 리가 없어요. | There’s no way I wouldn’t know. |
이 시험이 쉬울 리가 없어요. | It’s impossible that this test is easy. |
SOFT UNCERTAINTY
This structure is used to softly convey uncertainty, similar to “I think that…” or “I wonder if…”.
It is used for softer expressions of doubt, wondering, or guessing, often leaving room for uncertainty.
PATTERN
S + V + -나 싶다
비가 오나 싶어요. | I wonder if it’s going to rain. |
그가 올까 싶어요. | I think he might come. |
오늘은 조용할까 싶네요. | I wonder if today will be quiet. |
View More Examples:
시험이 어려울까 싶어. | I think the test might be hard. |
이 옷이 나한테 맞을까 싶어요. | I wonder if these clothes will fit me. |
그가 여기에 살고 있나 싶었어요. | I wondered if he was living here. |

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FAQs
How to use 틀림없다?
“틀림없다” means “there is no doubt” or “it must be true.”
It is used to express strong certainty about a fact or situation.
You typically use it after a noun or verb stem, often in statements where you are confident about something.
How is 싶다 used to express doubt?
“싶다” is often used to express personal thoughts or assumptions, similar to “I think” or “it seems like” in English.
While it can indicate some level of certainty, it is generally less strong than “틀림없다” and is often used when making subjective judgments.
Should I use 리가 없다 or 틀림없다?
“리가 없다” is used to strongly deny the possibility of something happening, similar to saying “there’s no way” or “it can’t be” in English.
On the other hand, “틀림없다” expresses strong certainty that something is true.
They are opposites in function—one affirms certainty, while the other denies possibility.
Is 싶다 both formal and informal?
Yes, “싶다” can be used in both formal and informal contexts.
However, in formal writing or speech, you might prefer “생각된다” or “것 같다” for a more polished tone.
What to use besides 틀림없다 and 리가 없다?
Yes, other expressions like “확실하다” (to be certain), “분명하다” (to be clear/obvious), and “말도 안 된다” (that makes no sense) can also be used to express certainty and doubt, depending on the context.
Does LTL provide Korean classes?
Yes!
You can study with us in Seoul, in our Hongdae location, or online if you prefer learn from home.
Contact us here if you have any questions.