UNDERSTANDING
Harry simply didn't understand. Back in his 5th year, Dumbledore had said that when Voldemort had tried to posses Harry, it had been Harry's heart which saved him – but why couldn't it save her?
She was, after all, his heart, his mind, his very soul. His love.
Yet loving her hadn't been enough. Had loving Sirius like a father, and Dumbledore almost like a grandfather saved them? No.
Her death, as Sirius' had been, was his fault. While on one of their walks – the walks that had kept Harry sane – she had embraced him, and whispered that it wasn't his fault there was evil in the world, and that she had stopped blaming herself for the attacks and opening of the chamber of secrets. She had told him that people made choices – good and bad, and that Sirius had made his choice, Harry hadn't forced him. Most importantly, she had told him that she loved him, and that was her choice, and that he couldn't change it.
She had been his life, and so full of spirit and love. That's what he didn't understand. How could someone so wonderful, and so loved, be so very dead?
But she would live as long as he did, for she would be in his memory and his heart.
Ironically, it was only after she was killed that he could find it in himself to finish off Voldemort. His rage and indescribable pain at her death had given him the power he needed.
At that moment, he finally understood. They had talked about choices, and Ginny had made hers.