Gu Xiaonuan had no idea that someone had already discovered her situation with Gu Xijue.
And that person who discovered them happened to be Shen Biran.
Shen Biran approached from the perspective of an adult, not wanting Gu Xiaonuan to become infatuated, which was entirely understandable.
If Shen Biran did nothing and just let Gu Xiaonuan and Gu Xijue develop like this, it would be a dereliction of duty on Shen Biran's part.
Gu Qingyuan wanted Gu Xijue to give him a reason, a reason that could convince him, only then would he allow him to refuse inheriting the Gu Family.
However...
"No reason at all, I just simply don't want to rely on the family anymore."
Because he doesn't want to rely on it anymore, he can't inherit the Gu Family.
Gu Xijue's reason sounded meaningful, but in reality?
This reason was just something Gu Xijue came up with at random to deal with Gu Qingyuan.