You can't change someone who doesn't see an issue with their actions.
Nobody's perfect. We make mistakes. We say the wrong things. We fall. We get up. We grow. We move on. We live!
I forgive people but that doesn't mean I trust them. I forgive them to let go and move on with my life.
The best revenge is always to just happily move on and let Karma do the rest.
Be careful who you trust and tell your problems to. Not every person who smiles at you is your friend.