Sakura had realised, on the night the broken, bloody bodies of her genin classmates were rushed to the hospital that Sasuke was not the angry, kind, proud boy she loved anymore. She had put her faith in him, even more than Naruto that he would want to return to the comfort and companionship of the leaf.
It may have been an effect of her own childhood misery and the salvation she had found through her friendship and subsequent rivalry with Ino, but in her heart of hearts she had always felt that Sasuke was very, very lonely. So to her his rejection of their friendship was also a rejection of the ideals she built her life around.
But now, on her knees in front of the Hokage, Sakura realised her mistake. Since the cursed seal had first consumed Sasuke in its sickly violet glow, he had been lost to them. She had felt aged before, seen death, seen suffering, and thought herself an adult.
But Sakura, with great and terrible clarity realised the truth-they were children. Sasuke happened to be one who had never grown up, frozen forever in his quest for revenge.
Given too much power and had weapons thrust into their hands far too soon, after all wasn't that what the Shodaime and founding Uchiha had sought to achieve? A society without child soldiers?
Sakura remembered her own helplessness on the hospital roof wishing she had the strength then to wrench the two apart before Kakashi became involved.
Kakashi- despite his unprofessional attitude was very much a Shinobi. Enduring. But also emotionally stunted. Under his questionable guidance Team Seven had fallen apart within a year of graduation. All of his leadership had been 'post-mortem' blaming himself for being a poor teacher and encouraging his remaining students only after they had found leadership in other areas. The only significant phrase not utterly frustrating in its impotency ('Sakura has the best chakra control of any shinobi her age') was stolen from the lips of a dead friend. By the time they reached him it was too late and 'everyone he ever loved' was dead.
Sakura still felt love for the little boy she had pined after and eventually gotten to know- who was gruff but considerate and protective of his teammates.
It had been in the name of this beloved memory that she attempted the assassination of Sasuke. Better, she thought, to be killed quickly before he sinks any deeper into the abyss, and by the hand of a friend. She prepared herself to carry that burden as a final duty to her teammate. Sakura had seen the reaction of the Cloud shinobi to Sasuke's' name and was fully aware of the sort of violent fate that would meet her once comrade at the hands of any shinobi nation apart from Fire or Wind.
But when he turned on her once, and then again, grasping the column of her neck Sakura realised that he was lost somewhere and maybe forever. It was so sad, she thought.