Eternal Happiness

Mang Lai Kwan, wanting to seek knowledge despite her father's opposition, often dresses as a man to go to school. On her ventures, she meets the royal grandson Temür Khan who is travelling in disguise and also a straight-up young hero Wongpo Siu Wah and the three become adopted brothers.
Although Temür sees through Lai Kwan's disguise, he does not expose her. Lai Kwan also has feelings for Temür. Her father arranges for her to marry Siu Wah, but at the same time, rich bully Lau Fui Bik asks for her hand in marriage. As the day of the marriage draws near, Lai Kwan decides to confess, but Temür is summoned back to the courts and asks Siu Wah to take his place to meet Lai Kwan. When Lai Kwan is stood up, she runs away. She later finds out that Siu Wah is her fiance and Temür has become the emperor of the Yuan Dynasty.
(Source: Wikipedia)
~~ Adapted from the novel "Zai Sheng Yuan" (再生缘) by Chen Duan Sheng.