When Yashamaru says, "I hate you, Gaara," it's more of a manifestation of his inner turmoil and frustration with the circumstances that led to Gaara's isolation. Yashamaru's statement is a tragic expression of his own feelings of helplessness, regret, and sorrow.

Did Yashamaru really hate Gaara? He hated the jinchūriki who ended his sister’s life. But he also loved the quiet, lonely boy who clung to his sleeve. Human emotions are not mutually exclusive. Yashamaru’s tragedy is that he was ordered to collapse his own duality into a single, lethal message. He chose to die as a weapon of the state rather than live with the unbearable weight of loving someone he was supposed to destroy.

In short, Yashamaru truly loved his nephew, but he was forced into a position where he had to lie to him as part of a cruel psychological experiment. The Cruel "Test" by the Fourth Kazekage

However, context is key to understanding Yashamaru’s true feelings. Yashamaru was the only person in Gaara’s early life who showed him kindness. He was the one who explained the concept of physical pain and emotional hurt, teaching Gaara that wounds to the heart are harder to heal than wounds to the body. Yashamaru risked his own safety to be near the unstable Jinchuriki, acting as a father figure and protector. This behavior is inconsistent with someone who harbors deep-seated hatred. If Yashamaru truly hated Gaara, he would not have invested so much time in trying to help him understand his emotions.

The goal was to see if Gaara could maintain control over Shukaku even when his emotional foundation was completely destroyed. Why did Yashamaru lie to Gaara that he hated him?

However, canonical revelations later in the series provide a much more complex and tragic truth. The Truth: Did Yashamaru Hate Gaara?

The crucial evidence lies in the Fourth Kazekage’s manipulation. The Kazekage ordered Yashamaru to attack Gaara and, if he failed, to lie to him. The goal was to test Gaara’s control over Shukaku. If Gaara retained control, he would be a weapon; if he lost control, he would be eliminated. Yashamaru, a loyal shinobi of the Sand, was bound by duty to obey his Kage. Yet, the lie he told was designed to break Gaara specifically because Yashamaru knew him best. He knew that the idea that he was unloved was Gaara’s greatest fear.

Ultimately, Yashamaru did not hate Gaara. The tragedy of their relationship is not one of hatred, but of love corrupted by duty and circumstance. Yashamaru was trapped between his love for his nephew and his loyalty to a village that saw that nephew as a monster. His final act was a performance meant to break Gaara so that he might eventually be reborn stronger. The lie hurt far more than the truth ever could, precisely because Yashamaru was the one person who truly loved him.

However, note the action before the explosion. Yashamaru spends the entire evening calmly treating Gaara’s wounds, playing cards, and speaking gently. He gives Gaara his name—“a demon who loves only himself”—as a twisted form of protection. A man who purely hated would have killed in silence. Yashamaru instead chooses to break Gaara psychologically before the physical blow. That is the act of a torturer, but also of someone ensuring the child will never trust again—which, paradoxically, protects the village from a potential rampage.