huàn / nàn / zhōng / de / nàn / yǒu / zuì / liǎo / jiě / bǐ / cǐ / jīng / lì / guò / de / tòng / kǔ

患难中的难友最了解彼此经历过的痛苦。

Fellow sufferers who went through hardship together understand each other's pain best.