Guy's Behavior

My crush is giving me mixed signals, how do I know if he likes me back?

My crush is a very shy person, from afar he somewhat shows me that he likes me (staring at me a lot, matching clothes w me since I met him, he even waited for me after class, sitting next to me and etc...). But when I try to interact with him he can't even look me in the eye or talk to me anymore, he just kind of ignores me (I kind of notice it happens when were around a lot of people or his friends). Another thing is when were around people I think he doesn't know, he chooses to be around me but he never says a thing.
My crush is giving me mixed signals, how do I know if he likes me back?
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