How do i tell if a boy likes me?

Okay there is boy that in the 6th grade(Im in 6th grade too)Hes light skinned and has the beautifullest smile ever, my best friend lives next door to him and she likes him alot. He is so quiet around me(hes not quiet around anyone else) and looks at me and stares… I really like him but im unsure if he likes me back.I REALLY REALLY REALLY like him. But it's hard cuz every other girl likes him.But hes not like that. Every other girl asked him out and he said no. he knows I like him but he acts like he doesn't care that I like him.Im kind of popular i guess and alot of boys like me but i dont like any boy but him. What do I do.?(Btw im using my cousins user.)!