Gu Shenwei had already thought it through, regardless of Slave Qian's warning.
Mama Xue must have been aiming for something big, or she had a powerful benefactor, and for that reason she dared to frame a plot in Golden Roc Fort. Gu Shenwei thought they should form a union, or even tell her his real identity.
He had considered all of the possibilities, and decided to abandon this plan. The main reason was the non-equivalence of their strength. Telling her the truth would give him nothing more but another handle in Mama Xue's hand to control him by.
He was only a fifteen-year-old boy, with mediocre Kung Fu, who wanted to slaughter the Shangguan family. Who would "form a union" with him?
Once he lost the value in use, Mama Xue would surely morganize him.