How will you recognize if the man is really serious with you?

if the man is serious with u than he will react as confused but he like u and he is just want u to tell some thing

I think you can understand it from the body language itself. But there are a few people who take it as a hobby to lure girls to their side and once they slip in, they lose the interest and go on for the next pray. I hate such guys, these guys enjoy the suspense and thrill or taming a girl, whatever. I think you could test him by telling him something bad and checking his reaction, if he seems to be concerned, he is really serious about you, otherwise he is not.