甲先生乙女士
[jiă xiān shēng yĭ nǚ shì]
'Jia Xian Sheng Yi Nv Shi' literally means 'Mr. Jia and Ms. Yi.' 'Jia' and 'Yi' are common placeholder words in China for naming unnamed individuals; it’s similar to using A and B elsewhere. This person might want to keep their identity anonymous or be humorous in a unique relationship setting between a man and woman.