You need remorse.

"Regret is where you admit wrongdoing and say, 'It won't happen again' and then say, 'Can't we just move on?'

Remorse is where you look deeply into the eyes of the person you beat up, see the damage you did, let them see that you accept responsibility for it, and then say, 'I did that. I was wrong. I'm sorry.' No excuses, no explanations, no defenses."