Your girlfriend condition is similar like me .Me too has bad memory of my past relationship. Now I have been single a quite long time, though threre are some guys out there that have been interested at me,they are nice people but it just that my true feeling had lost.It hard for me to express my true feeling again, so for me if I am in relationship, for this time that not right for me yet, I think I my self will be act not really serious for the relationship, maybe I could hurt the guy that with me at the time.Yup,maybe I my self afraid to get hurt too.
Girls condition like your girlfriend and me, need a time to break the wall.Give her time, do not push her with question "do you love me?" because she's not clear about that right now.Just be steady in your relationship with her,whole her when she's in emotional.Say that you there with her, say she's beautiful and you love her. You'll now she love you when she start concern about you, she appreciate you, she need you and you'll know by looking her eyes, you can feel it.Try your best to win her heart.Good luck!