铁石心肠: heart of stone [steel]; a rocky [stony] heart; be dead to all feelings; be iron-hearted [hardhearted]; marble-hearted; steel one's heart against pity; unmoved by feelings
热诚: warm and sincere; enthusiasm and devotion; cordial 短语和例子热诚地希望 sincerely hope; 热诚欢迎 cordially welcome