Understanding is not so easy

Hi, guys, I’m Ashley. I’m on the 3 course of college and I have a problem. SO there’s a cute guy in the class but I am not sure if he likes me back. I don’t understand when people really show some signs of affection. He was kinda smiling at the first time bur then went completely serious. Those offs and ons drove me crazy but recently I’ve bumped into casanova style. They definitely have some tips here. Don’t know, but I’ll try. Wish me luck!