He gaslights Gaara, telling him that his mother hated him and cursed the village. He twists the knife of rejection so deep that it severs Gaara’s connection to humanity. It is a calculated, heartbreaking lie meant to break the boy's spirit completely. As he detonates his final explosive tags, he isn't trying to kill a target; he is trying to kill Gaara's heart.
Here is a character piece regarding Yashamaru. yashamaru
"The pain of being lonely... is not something that heals as easily as a physical wound. It’s a pain that stays in your heart... forever." — Yashamaru to Gaara He gaslights Gaara, telling him that his mother