Bodyguard in Disguise

Ye Yao changed her name to Bai Fei and dressed as a man to infiltrate the Ling clan, the most powerful family in A City. Bai Fei became the trusted right-hand man for the Ling family's unruly heir Ling Ye, and he treated her like a brother-in-arms. Until during an undercover mission where Bai Fei was forced to dress up as a woman, and Bai Fei couldn't help herself and kissed Ling Ye after getting drunk.

(Source: Tencent, translated)