Screenshots from Youtube
Facebook  memes creator/pages admin/comedian Mel Oliveros upload a 4 minutes video to  show a sign of a guy when he is serious and interested to you.

You'll definitely know when a guy is seriously interested to a girl when you start to notice these things:

He is needy of her attention.
He talks a lot about you to his friends and family.
He always waits for you to arrive or to pass somewhere.
He feels lost whenever he looks in your eyes.
He finds himself getting his eyes stucked staring at her.
He feels that the world is turning slow whenever she comes or passes by.

These things are the obvious signs when a guy is interested to a girl. But please be observant if he only wants to trip or he really likes you.
Love is indeed in the air.