What are some signs a girl really likes you, but is putting up a "wall" because she's been hurt before?

She showed a whole lot of interest before that I didn't realize. I think she's toned down the "interest-showing" on purpose because she's been hurt before (ex cheated on her, this guy she liked made out with her and got a girlfriend the next week)
What are some signs a girl really likes you, but is putting up a "wall" because she's been hurt before?
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