早知今日何必当初

早知今日何必當初
zǎozhījīnrìhébìdāngchū
  1. if I (you, she, he...) had known it would come to this, I (you, she, he...) would not have acted thus (idiom)
  2. to regret vainly one's past behavior

CEDICT

Entry Composition

1 早知 zǎozhī to know in advance
2 今日 jīnrì today
3 何必 hébì
  1. there is no need
  2. why should
4 当初 dāngchū
  1. at that time
  2. originally