Sakura trained. Trained harder, really, than should have been possible for anyone, let alone someone as weak as she had been.
First, it was with Tsunade, after Naruto had gone after Sasuke without her. It was then that she had realized how useless she really was.
Then it was with Naruto and Kakashi, after she and Naruto had finally found Sasuke only to lose him again. Despite three years of work and study, she had still been no help at all. She was still not strong enough.
And then she had trained constantly, after she had watched in utter horror and aching sadness as Sasuke slipped his sword into Naruto's gut without even a ripple of regret in his black eyes. Though she healed Naruto, something inside of her withered and died. She knew now that people really could change, and love was not endless.
For a while, her life had been an endless cycle - train, eat, train, study, train, sleep. She trained with Gai, with Kurenai, with Naruto, Neji, Lee, with Anko. Anyone who was willing. She trained alone when she could find no one else join her, when the others chose to rest and gently suggested that she join them. But she had no time for rest.
Sakura had a goal now. A clearly defined goal.
And now she was on the verge of reaching it.
She grasped a thick handful of silky black locks in her impossibly strong fist and yanked back. He would have glared at her with his crimson eyes if she had not gouged them out during the fight. Intimate knowledge of human anatomy combined with precise chakra control could be used for much more than healing. His breath was heavy as she pushed a kunai to his soft, pale neck. Amazingly, he whimpered, just once, as he felt the tip pierce the skin, and he tried to turn his head right, left, staring blindly through his empty eye sockets.
See, Sakura knew there was nothing she could do to Sasuke that would upset him. Nothing, not even his death at her hands would faze him. So she had changed tactics.
She really could not have timed this any better, really. Sasuke appeared right when he was supposed to, right when she knew he would.
There was nothing she could do to him that would give him a fraction of the grief he had caused her. But there was something she could take - the only thing he cared about any more.
Sakura stared directly into Sasuke's shocked eyes, smiled, and sliced her kunai across Itachi's throat.
Revenge really was sweet. Sasuke would never know how sweet it was.