The Ninth Prince grew up with Su Yang and the others.
As good brothers, they naturally hoped he could achieve his desires and leave no regrets in life.
As elder cousins, they hoped their cousin could marry a perfect gentleman who would love and cherish her throughout her life.
They trusted the character of the Ninth Prince, but he was already feared by the Crown Prince.
If his feelings for Shen Yue were not so deep, unable to remain loyal to her, potentially having many wives and concubines in the future, hurting their cousin's heart, Su Yang would never agree.
If the Ninth Prince truly loved Shen Yue and would marry none other than her, Su Yang felt he could make an effort; not because he lacked ambition, but because true brotherhood should not make the Crown Prince suspicious, and avoiding marrying the woman he loves just to alleviate such suspicions would be rather cowardly.
A person like that could never be their brother.
