This was only because they were from the same Prominent Family. Had it been any other family, daring to make such a request would have gotten him thrown out directly.
Wang Shouzhe had originally thought of tapping into the Imperial Household's abundant inheritance of True Methods, but was outrightly rejected by the Great Emperor.
Indeed, even the Lingyun Holy Ground, whose motto is "Educating the World," would not grant the core inheritance of any True Method lineage to anyone who was not truly committed. How much more so for the even more exclusive Imperial Household?
Unless one was willing to marry in... perhaps preparing to become a sort of Prince Consort.