Should I trust him or not?

I was really shocked when the guy that I have crush with likes me back. Turn out that he liked me in a long time. He told me words that he is serious about liking me and all. But...

Should I trust him? Should I believe him?

I am blinded for that fact that something is holding me back in believing him. Though I am pretty much happy when I am with him, the way I look into his eyes is just amazing. And when he talks to me, he looks at me in the eyes with such joy and sincerity. But I seem not to recognize that, even his effort I seem to ignore it.I told him that I believe him though I don't.

How can you tell if a guy is serious about you?

Ah so many questions in my head right now can't really organize my thoughts. But I do like him. He's just... amazing.