Depends on the guy. Some guys who have low self esteem would be intimidated, but some would not, even if the girl is way out of their league.
If a guy looks at you and is nervous talking to you...I mean you can sense from his behaviour if he likes you, but does not say anything. He enjoys talking to you and laughs with you. He seems to be in a good mood when he sees you. Gives you a compliment how what you say is the funniest or smartest thing in the world because you said that. The way he looks at you is a dead give away...if he has this "lost" look on his face, that means he likes you. I mean, you can just sense it, can't you? I can always sense it, even before he acknowledges that he likes me.