卖片儿汤

Traditional (Taiwan): 賣片兒湯

màipiànrtāng ㄇㄞˋ ㄆㄧㄢˋㄦ ㄊㄤ

    • to fool people with pleasant but empty words

Saying俗语俗語

Idiom惯用语 · Rarely used now

Literally
sell noodle-flake soup
Meaning
To fool people with pleasant words that have no substance, like a soup that is mostly water and leaves you hungry.

Sources