For everything - how he’d treated her at Hogwarts, how he’d bully her into hating her own looks, how he could not defend her when she laid, tortured, on the black wood of Malfoy manor, bleeding and screaming to death. Everything, one small word which encompassed years of mistreatment by her own peers. He could have listed everything that he’d done to her that was wrong, she knew that he knew, but he’d settled on  everything  : he was not shying away from his mistakes.