The antonyms for "most hard-hearted" are words that convey warmth and compassion. These include kind-hearted, compassionate, empathetic, tender-hearted, sympathetic, and caring. A kind-hearted person is often loving and gentle, while a compassionate person shows understanding and concern for others. An empathetic person is one who can relate to another's emotions, while a tender-hearted person is easily moved by feelings of others. A sympathetic person is one who feels sorry for someone else's misfortune, while a caring person provides care and attention to someone. Together, these antonyms form a spectrum of emotions that contrast with the coldness and indifference of a hard-hearted individual.