How do u no wen sum1 loves u

Not really. Depends on how much you trust him as to how much you believe him.

If your fella is the same age as you then I really wouldn't read too much into it to be honest.

No way to tell really. Some people lie about it to get what that want, some people think their in love when really its just infatuation or something. I don't think you can be in love at a really young age because you don't have enough life experience to justify your feelings or compare, but I could be wrong.

When all else fails, listen to your heart.

o.O when he starts to feel werid around you... or always talking to you... or ? o.O just becomes really close to you... that how it works =/

You can never know, you just have to trust him and see what happens in the future.

I guess you have no reason NOT to trust him if he says he loves you, its HIS emotions after all, but he may THINK he loves you and not really, so he may be confused, or maybe he really does. You can never know for sure, you're not him.