I asked someone who knows the girl I like to find out if the girl I like likes me. This person came back to me and told me that the girl I like likes someone else. I then told this person to tell the girl I like that I like her. Out of the blue, a guy in the class that the girl I like is also in asks me if I like the girl I like. I said yes and the girl I like smiled whenever she was looking at me that full lesson. The next day, the girl I like and her friends were looking/staring at me. When in class the day after her friends were staring at me, the girl I like was hovering around near me and talking to me. Today, she walked passed and her arm brushed against me (happened 2-3 times) (most likely on purpose), I caught her staring at me and she looked away. She again seemed to hover near me (one time standing near me and after some time telling her self why am I standing and sat back down). Her legs were crossed over and the top leg was pointing in my direction or stretched towards me.

I had found out from the person I asked who knows the girl I like that the girl I like is dating the guy she likes. Yet she is showing me these signs of liking me.
Why is she showing me these signs if she likes someone else?
Did she lie because she doesn�t want to pass gossip about our relationship?