Zhu Xinyan had indeed willingly signed the prenuptial agreement to marry Su Yukan and lead a comfortable life. In fact, many couples in the circle of the wealthy clearly had such agreements about property distribution before marriage.
Not only did the males do this to ensure the safety of their assets, but many times the females also did so to protect their own property, as usually, the men and women in this circle who married were both powerful.
In simple terms, this meant, "you worry I covet your property? I'm worried about you eyeing my property too!"
Since everyone had the same reservations, everything was clearly detailed in the prenuptial agreements. This avoided disputes during a potential divorce, and during the marriage, there was mutual benefit and cooperation for a win-win situation...
Su Lu felt ashamed when she talked about it, as her own marriage had indeed been of this nature.