The Tin Woodman and the Scarecrow are regaling each other with tales at the Woodman's palace in the Winkie Country when a Gillikin boy named Woot wanders in. After he is fed and rested, Woot asks the Woodman how he became made of tin. He relates how theWicked Witch of the East enchanted his axe and caused him to chop his body parts off limb by limb, because he was in love with her ward, Nimmie Amee. Each chopped limb was replaced by the tinsmith Ku-Klip with a counterpart made of tin. (Since Oz is a fairyland, no one can die, even when the parts of their body are separated from each other.) Without a heart, the Tin Woodman felt he could no longer love Nimmie Amee and he left her. Dorothy and the Scarecrow found him after he had rusted in the forest and went with him to the Emerald City where the Wizard gave him a heart. Woot suggests that the heart may have made him kind, but it did not make him loving, or he would have returned to Nimmie Amee- This shames the Tin Woodman and inspires him to journey to the Munchkin Country to find her.
(Excerpt from Wikipedia)