Responses
Uhm, I dont think heejae cares if garam likes him, it's for that the fact, he wants to see how long it takes for garam to endure all the pain inflicted on him by a blade like him. And he doesn't hold back from showing his worst sides to garam though- in fact he reveals much worse side to garam than he did to anyone. It's a test not to see if garam really likes him, but to see how long his love lasts and turns into bitter hatred.
So hard to admit, but I can really relate to Heejae's feelings. I tend to self-sabotage and "test" people to their limits just to see if they would still like me or love me as their friend, even after seeing my worst side.
Heejae found someone who genuinely tries to understand and care for him, but I guess he's still doubting whether Garam's feelings are sincere or not. Since heejae did nothing but hurt the people around him, I guess he's finding it hard to believe that someone like garam is there for him. We see him holding himself back because, although he wants to test Garam, he's scared that Garam will eventually leave him if he shows his worst side, similar to what happened with his former manager.