铁打心肠

Explanation: Cast-iron into the heart like that. Describe the strong man's mettle. 　　Source: Song Anonymous "wrong conduct" drama eighth horizon reason people out of monopoly, they do the iron-hearted Zhu Lei dumping. " 　　Examples: Daddy, you a moment of anger, killed him, so if you see Oh, the pain with you - also sad. ★ Ming Xu Lin, "embroidered jacket is from the mind responsible for good."