Zài tiěxīncháng de rén, jiàndào zhèzhǒng chǎngmiàn yě huì dòngróng.
Even the most iron-hearted person would be moved by a scene like this.
Tips
usage
Usually neutral-to-positive, conveying strength of resolve. Compare 狠心 (cruel, negative) and 心肠硬 (a bit harsher). A doctor, judge, or soldier might need 铁心肠.
