後悔Remorse is a strong feeling of sadness and regret about something wrong that you have done.

a gnawing distress arising from a sense of guilt for past wrongs 

Moral anguish arising from repentance for past misdeeds; bitter regret. See Synonyms at penitence.

Deep regret or guilt for a wrong committed.

a strong sad and guilty feeling about something that you have done wrong

深い後悔, 悔恨, 良心のとがめ, 自責の念