repenter

intransitive verb

1. to feel sorry or self-reproachful for what one has done or failed to do; be conscience-stricken or contrite: often with of
2. to feel such regret or dissatisfaction over some past action, intention, etc. as to change one's mind about: often with of: to repent of one's generosity
3. to feel so contrite over one's sins as to change, or decide to change, one's ways; be penitent

transitive verb

1. to feel sorry, contrite, or self-reproachful over (an error, sin, etc.)
2. to feel such regret or dissatisfaction over as to change one's mind about: to repent one's kindness