I don't know if I love you or not,
I don't know whether I've fallen in love or not,
I don't know how deep love is.
Xu Nuo fell in love with a person. That person was originally named Zheng Yan, and later named Xu Yan. So the person Xu Nuo fell in love with was his sister...
It's just bullshit anyway, I can only write bullshit