How can I comfort my friend who was abused in her teenage ?

Recently my best friend told me that she was abused in her teenage by her cousin.From then onwards she started having bad thoughts, became addicted to porn and masturbation.She feels that she is a great sinner, she would have been a pure person if her cousin didn't do such things to her, sometimes she feels like killing herself.She feels she has lost her worth.She is suffering from depression but she somehow manages to put on a happy face in front of others.How can I comfort her,I just love her very much.She is from a good Christian family and that makes her guilt feeling worse.