吾若为皇你定为后你若为皇我必为后
[wú ruò wéi huáng nĭ dìng wéi hòu nĭ ruò wéi huáng wŏ bì wéi hòu]
This username expresses deep love and commitment between two people. If one were to be the emperor, the other would definitely become the empress, indicating their unbreakable relationship and mutual support.