Guy's Behavior

How do I know if this leo guy likes me?

ok so there's this guy I seriosuly can't get out of my head-i really like him. he's a leo (im a taurus), and I need to know if I'm getting the right vibe from him. so lets be honest for a minute-where everyone tells me I'm beautiful, and have a wonderful personality and great sense of humor...i am so shy, its ridiculous. I freeze up around guys I really like (dont take that the wrong way my love life is not nonexistant ;)) and to be perfectly honest, I'm kind of intimdated by him-hes extremely outgoing, probably the most popular guy in the school (just my luck, where me and my friends are just kinda friends with everyone >.<), really funny and loveable...but he treats me sort of different, I'll catch him staring at me in class, when I sit by him he starts to breathe heavier, he's very quiet and shy around me sometimes and othertimes he'll just go ahead and start a conversation...the most convincing thing for me was that one week I caught him mouthing words in my direction, but I couldn't tell what he was saying. the other thing was I was talking with my friend once about my ex, and he started badmouthing him. to top it off, he saw me with one of my guy friends and he got all offended and start teasing us like "aw, cute couple"...so I should be able to believe he likes me, but I don't, cus it just seems like he's not the kind of guy who should like a girl like me.
How do I know if this leo guy likes me?
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