If Xue Wubin hasn't died and is near Wangcheng City, then where can he be found?
This question format would surely make the Booksmith able to give an answer, whereas asking directly about Xue Wubin's whereabouts would hardly have such an effect.
Of course, the downside is that Xu Cixi might not be able to find Xue Wubin at the location provided by the Booksmith, but this downside is not to be worried about.
Xue Wubin's name had appeared on a barrel, and it had also drifted at sea near Wangcheng City; to say he's unrelated to Wangcheng City is certainly impossible.
If even Wangcheng City has no trace of him, then he's probably truly dead.
Xu Cixi is not incapable of accepting her brother's death; all these years, she has simply been waiting for a relatively accurate result.