Guy best friend is your non-romantic male soul mate. Usually when a girl is deprived of a brother, this male ends up being the replacement. They are as close as siblings and he means the world to her. He is referred to as the "guy best friend" usually when the girl has best friends who are mostly girls.
Guy best friend(男闺蜜)就是跟你没有恋爱关系的男性灵魂伴侣。如果一个女孩失去了兄长，这位男士就会成为替代品。他们亲如兄妹，他是她的全部。因为这个女孩的好朋友大多都是女性，所以，这位男性好友就被称为“男闺蜜”。
While most of the time these two remain best friends, it is usually the male that tends to fall for the female. Females who do fall for their guy best friend usually keep it quiet in fear of losing their best friend.
Rose says that Victor is just her guy best friend. She has no feelings for him whatsoever.