潘金莲给武松敬酒 pānjīnliángěiwǔsōngjìngjiǔ [xiehouyu] with bad intentions
A two-part allegorical saying where the first part is "Pan Jinlian offers a toast to Wu Song" and the unstated second part is [[不怀好意|不懷好意|bu4 huai2 hao3 yi4]], meaning to harbor ill intentions; used to describe someone acting respectful while secretly hiding a malicious motive.