The thing that hurt about unrequited love is the fact that we often look for people who were never there in the first place. Xiu's feelings were uncertain as she heard him calling Chen Xiu as his unrequited love. She honestly never thought that there could be someone whose eyes would only look for her. That reality of being unloved and abandoned by everyone around her had left a huge imprint on her mind in her previous life.
Perhaps, that was the reason that she never even noticed that Darren was in love with her. Because the possibility of someone like him loving her seemed too farfetched. Yes, she was loved by millions of her fans but none of them fell for her real self. They fell for the artist she was, not the person she was. But the same reason was why she always felt so close to Darren even without meeting him in person because he knew her as a person and not as a star.
