Gu Xiaonuan was determined, and after failing once, she decided to keep trying.
In any case, she would do anything to get Si Yuchen's signature.
Si Yuchen understood the series of situations occurring in Sea City, and the outlook didn't seem optimistic.
Gu Xiaonuan was still unaware of Shen Biran's disappearance, and it needed to be resolved quickly to prevent her from rushing back to Sea City once she found out. If anything happened, Si Yuchen's guilt would multiply.
Si Yuchen felt guilty toward his fake marriage partner before the divorce, to the point where he didn't want to divorce Gu Xiaonuan.
However, Gu Xiaonuan didn't appreciate it. Everyone has their own life, and so does Gu Xiaonuan.