You can guess what's gonna happen🤷🏻♀️, it's an arranged marriage story anyway. Wen KeXing had travelled to West Bengal in India, (you can imagine the partitions were there back then) and learned to play and sing a lot of classical music. (You can also imagine these songs existed back then.) The emperor is pleased by his music and gives an imperial edict for him to marry his eldest son, Zhou ZiShu.