Negative sentences in Korean are generally made in two ways:
-by prefixing any verb with 안, and conjugating as normal.
-by removing the 다 from a verb, affixing 지 않다 on the end, and conjugating from the 않다 area, which will become 않아, 않아요 and so on, as with all verbs that have an 아 sound.
- 밥을 먹어요 - (I) eat food.
- 밥을 안 먹어요 - (I) don't eat food.
- 밥을 먹지 않아요 - (I) don't eat food.
- 뽀뽀를 해요? - (You) kiss?
- 뽀뽀를 안 해요? - (You) don't kiss?
- 뽀뽀를 하지 않아요? - (You) don't kiss?
The 지 않다 ending emphasizes the negative a bit stronger than the 안 prefix.