Tiancai Xiao Du Fei Zhi Yun Xi Chuanqi

The youngest daughter from a family of healers, considered plain and overlooked, marries a prince from Kingdom Tianning. On their wedding day, as the wedding procession arrives, the mansion doors are closed, leaving her to enter alone. Inside, she secretly reveals her true talent as a skilled and beautiful medical expert. That night, she treats an injured assassin and offers to keep his presence a secret if he leaves quickly. The assassin, however, refuses to leave, stating it is their wedding night and asking where he should go.