Have a mouth as sharp as a dagger, but a heart as soft as tofu

Similar sayings:

Honey in his mouth, knives in his heart Honey in his mouth, knives in his heart
Know thyself to know others, for heart beats like heart Know thyself to know others, for heart beats like heart
He that has no money might as well be buried in a rice tub with his mouth sewn up He that has no money might as well be buried in a rice tub with his mouth sewn up
Donkey’s lips don’t fit onto a horse’s mouth Donkey’s lips don’t fit onto a horse’s mouth
Out of a dog’s mouth will never come ivory tusks Out of a dog’s mouth will never come ivory tusks

Chinese sayings and proverbs