Need istance on trying to read a girl I've dated on/off for awhile and known for longer.?

This girl and myself met way back 7-8 years ago at the end of HS. She and myself were both in relationships but now admit to liking one another. I went into a LT relationship when she says she liked me, and then the opposite happened. She has before once went on a break with boyfriend at the time and came to me... hung out once or twice and then she was confused when he wanted her back... I did not put up a fight, I told her to go back to him (I ume it would have happened given their history) Well, she broke up with him again and this time it seems for good. She starts calling me, telling me she always thought/thinks about me, wants to see me..and when we do get together she is very straight forward with comments like, "why do I like you so much", etc. However, I don't know if she's on the rebound and kind of a sappy girl or being true. I'm the kind of guy who will push her away b4 she pulls a "confusion" bit w/ me. How do I know if she's an honest girl and not a wierdo whose lost?