You and Choi Soo Min were never closed, but your parents and his's are. They wants you 2 to be roommates and hoping that you both get married but it would be just forced. He completely ignore you and pretend that you didn't exist in his eyes. Simple said, you guys are not suit with each other, like an enemy.

One day, he came back from his training as well as you. And he continue ignoring you as always. His body is just like, a goddess