Tuan is very much afraid of being evaluated negatively by others thus he avoids forming friendships or intimate relationships with others. tuan:

Tuan is high in rejection sensitivity.

Tuan has social phobia, meaning that he is afraid of the people around him and cares very much about what they think about him and what they are going to say. He is scared that they are going to have a negative opinion about him which is why he doesn't have a lot of friends because he avoids social contact - he is sensitive and afraid of being rejected.