Forgiving your girlfriend for her past mistakes is not an easy task. However, it's important to understand that no one is perfect, and we all make mistakes. The first step towards forgiveness is accepting that her past is beyond your control. Try to communicate with her, and express your feelings without being judgmental. Listen to her perspective and try to understand her situation. Forgiveness takes time, so be patient and give yourself and your girlfriend time to heal. Remember that forgiveness is not just about letting go of the past but also about moving forward and building a stronger relationship.