ML feels in love because of FL's abilities not because of she is cute or childish.

ML is successful and smart man. At first, he hates FL because of misunderstanding but, later FL impressed him by her abilities so he slowly feels in love with her.

Ex giant (secondary couple ) or maybe Princess agents 

Story of Yanxi Palace! the emperor is in denial for so long, and everyone tells him he's in love with her

Empress of China

Legend of Mi Yue (now on youtube)

Empresses in the Palace

Story of Minglan

Princess SIlver