磨炼 (mó liàn): see 磨練|磨练[mo2 lian4]

He taught in a rural area for three years, and the hard life tempered his will, making him stronger.

After being tempered by many competitions, this young athlete's skills and mental toughness have greatly improved.

The setbacks he encountered while starting his business tempered him and taught him how to handle pressure.

Military training tempered the soldiers' perseverance, making them never give up in the face of difficulties.

Living alone in a foreign country is hard, but it can also temper one's ability to live independently.