疾风知劲草，烈火见真金

jí fēng zhī jìn cǎo , liè huǒ jiàn zhēn jīnjifengzhijincao,liehuojianzhenjin

1. lit. sturdy grass withstands high winds and true gold stands the test of fire (idiom)
2. fig. strength of character is revealed in a crisis

Study it in Yanamino