How do you tell that a boy like likes you?

Katelynn
So I like this boy and I have told him that I like him and he is okay with that. He is like my best friend and he tells me everything and I tell him everything. I will tell him who I like and he will tell me who he likes and so on, but whenever we get around each other he get nervous and very flirty acting. Is this a sign that he likes me?