Why a girl hides her stories from me?

She hides her stories from me, not all the stories, specifically some of them, stories about love, brokenheart and things like that, she just broke with his boyfriend 1 week ago and. I like you and I think she likes me too, we have flirted before and we didn't get into a relationship because she has a boyfriend already, my friend told me she is single now and I told her I want talk with her about us when I see her again, she is ok with it, but she started to hide her stories and doesn't look at mine or see mine in hidden mode. I know she hides it because my friend told me, she doesn't hide it from him, I wonder why she acts like this. What should I do?
Why a girl hides her stories from me?
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