iron hand in a velvet glove
Rigid in the soft outside is a Chinese word, pronunciation is gngzh ō NgR ó UW à I, refers to the person's soft outside but hard inside character.
Definition: rigid, strong; middle: inner, inner; soft: weak, soft. The surface is smooth and the inside is strong. it comes from "thirty six stratagems, hidden sword in a smile": "believe in it and keep it safe, use Yin to draw it, prepare for it and then move it. Don't make it change. It's hard in the middle and soft in the outside." used as attributive and adverbial; refers to personality
iron hand in a velvet glove
it happens that there is a similar case - wú dú yǒu ǒu
bury oneself in outdated writings - zuàn gù zhǐ duī
cut off the long and compensate the short - zhé cháng bǔ duǎn