Struggling to Forgive

How can one get to the point of forgiving someone who has gone OUT OF HIS WAY to harm and scar you for his life. Instead of realising his mistakes this person, is in fact proud of his actions and looks into the eyes of his victim with an air of superiority, conveying something like – I did what I did to you and there was nothing you could do to stop me.

Unfortunately, I have such a person in my life. It would bring a lot of peace to my heart if I could make myself forgive him. I would be eternally grateful if you could tell me what’s the best way to do that since on my own I find it impossible to do so.