My girlfriend is a strong Christian and where as I am a Christian, I don't exactly share the same beliefs as her. We recently broke up after three years because her parents wouldn't allow it. I respect her beliefs, and I have been willing to hear more about it, but I know it would obviously be wrong to force it upon myself just to be with her. Do you have any advice for me? Walking away isn't really an option because we love each other.
You are correct that pretending to accept a belief just to be with your girlfriend would only be hypocrisy (putting on an act). It doesn't matter what you believe or what your girlfriend believes; the only thing that matters is what the Lord says. "For do I now persuade men, or God? Or do I seek to please men? For if I still pleased men, I would not be a bondservant of Christ" (Galatians 1:10).
I don't know if your relationship is salvageable or not. You don't believe as she does. She won't accept someone who believes differently from herself. You can't force someone to change, so it looks like you will need to find someone else.