项庄舞剑/ 項莊舞劍 xiàngzhuāngwǔjiàn to have an ulterior motive
(idiom) an elaborate deception hiding malicious intent; literally means "Xiang Zhuang performs a sword dance," referring to a historical plot to assassinate 刘邦 liúbāng during the 鸿门宴 hóngményàn feast