A proverb meaning that hardship and adversity refine a person and make them better or stronger.
留学中の苦労を振り返り、彼は『艱難汝を玉にす』という言葉を思い出した。
Looking back on his struggles studying abroad, he remembered the saying 'hardship makes the man.'
困難なプロジェクトを乗り越えて、部長は『艱難汝を玉にすだね』と部員を励ました。
After overcoming a difficult project, the manager encouraged the team, saying 'hardship makes the man.'