Why does Xiuyuan say JK Rowling is a mermaid princess?

Although the mermaid princess is beautiful and brings beauty to people, she will eventually disappear. Zhu Yuan knows Rowling's background very well, which is very different from himself. He thinks that no matter how much he likes Rowling, she will not be with him forever, even without her mother's objection. I always feel that when I am not sure about each other, Xiuyuan sometimes has different opinions, especially in front of her mother. Personal opinion, hehe ~ ~