Korean grammar patterns › Level 4
-지 않을 수 없다
cannot help but …, have no choice but to … (double negative)
Level 4 · TOPIK II · intermediate
How to use it
A double negative meaning the action is unavoidable — because of feelings (can't help laughing, being surprised) or circumstances. Somewhat formal; common in writing and speeches.
Forming it
| 울다 | → 울지 않을 수 없었어요 |
| 놀라다 | → 놀라지 않을 수 없어요 |
| 인정하다 | → 인정하지 않을 수 없어요 |
Examples
그 영화는 너무 슬퍼서 울지 않을 수 없었어요.
That movie was so sad that I couldn't help crying.
증거가 이렇게 많으니 인정하지 않을 수 없어요.
With this much evidence, I have to admit it.
Compared with similar patterns
-(으)ㄹ 수밖에 없다 (G3-010) is more common in speech and focuses on 'no other option'. -지 않으면 안 되다 (G3-014) and -아/어야 하다 (G1-033) express obligation, not an unavoidable reaction.