Spoilers for chapter 483, in case you haven't read up that far yet.
"You know, you're a total ass."
The Sakura in Sasuke's mind is more beautiful than the real one, but also crueler and harsher in her words.
Sasuke doesn't like to visit her. She holds all of his memories of the real Sakura, everything he had ever felt in regards to her—annoyance, protectiveness, friendship, and a whole other tangled mess of emotion that he refuses to investigate or name. Even being in her presence for a short time means that the barrier erected to block out his memories thins dangerously, forces him to review old recollections and discomfiting promises.
There's a Naruto in his head too, but Sasuke isn't half as afraid of him. The only feelings he brings to mind are the drive to improve to defeat him, to crush the other boy to a pulp.
That Naruto hasn't been seen in a while, and it hasn't occurred to Sasuke to wonder why.
"You are, to honest, much worse than an ass. You're also the stupidest thing to ever walk the path of a shinobi." continues this Sakura. Her hair is longer than her real-life counterpart, Sasuke notes idly how she runs her fingers through it, uncaring of how it stretches the skin on her face taut or how it exposes that forehead she used to hate so much.
Really, he doesn't know why he visits her at all. She's still annoying and worse, because she's not real.
"You asked her to kill someone who had never harmed her, and was bleeding to death in the dirt. Someone who also loved you." She snorts lightly, looking down at him from her position on the bed. "And you think you know her so well."
On some level, Sasuke is offended. He knows Sakura very well. Why shouldn't he? He's been talking with her for years, now.
"You are horribly injured, being manipulated by that bastard of an ancestor, have a dying teammate who did and does still have valuable skills—" Sakura ticks off his circumstances on her fingers, holding them up and wiggling them at him. "And here she comes, all offering to join you, to help you—granted, she was actually on a mission to kill you, but I don't think it lessens the overall impact. You could have handled this lot better than you did. Ass."
Sasuke scowls and turns away from her, wondering idly how long this bout of madness will last. He doesn't fully understand his own mind's workings, and why they bring him to have this pointless conversation with a version of a girl who was an old teammate whom he just attempted to kill.
"Hey, don't look away from me."
This Sakura's angry now, and footsteps indicate that she has stood and crossed to grasp the bars of her cell door, as she is wont to do when she gets impassioned. He turns to look at her properly, fully. He likes how this Sakura looks when she gets angry: she looks dangerous. Someone worthy of challenge, someone he can acknowledge. The true Sakura doesn't look like that at all.
"Wrong," says this Sakura, and she's smirking at him now. She always knows his thoughts—she exists in his head, of course she knows his thoughts—and he chooses to listen.
"How am I wrong?" he asks, humoring her. Indulging her.
"She's really strong," says this Sakura, smirk growing wider. "You like getting me angry—wait till you see her again. She won't hold back. Maybe she'll actually kill you." There's a note of sadistic glee in her words.
She leans forward a little, bangs dipping in front of her eyes. "You'd like that, wouldn't you?" Her eyes are half-lidded, lips curved up in a sweet smile.
Sasuke can feel his anger rising, and he stands, walking right up to her cell, until there are only inches separating them. She cannot touch him, has tried, has failed. When he was younger, sometimes he would let her. Now, he doesn't.
"It does not matter. I will not encounter you again. If I do, I will kill you." Sasuke looks Sakura right in her too-dark eyes, "You don't matter to me."
"Wrong again." This Sakura laughs, full and throaty and a little sad too. "Well, sort of. You don't care anything for me. But you care for her very much."
She reaches out, and against all expectations, all prior experiences, her fingers gently graze his cheek.
"You made me as a substitute, don't you remember?" She's still smiling, but it's slightly broken. "To visit when you were lonely, and to let others lock me away with greater ease. I'm not really Sakura Haruno. You gave your memories of her a form—as you did every memory of every person you have ever loved. The better to lock away and render yourself a blank slate."
Her hand cups his cheek. Sasuke can feel the roughness of her palm, the gentleness of her touch.
"But you've seen her," her voice changes—it is lighter, almost giddy. She starts to laugh like a little girl, not like the woman she has been playing. "You've seen her, and I will cease to be, and it's already happening, and you still don't understand, you foolish boy."
"What don't I understand?" He finds himself asking.
There are tears running down her cheeks. But she's still smiling. Her thumb brushes over his cheekbone, still achingly gentle. Her hair looks shorter, and are her eyes starting to lighten…?
"It's already starting," she says softly, "You are coming back."
She then punches him in the jaw.
Sasuke jolts awake in the forests, breathing hard, his heart racing.
Sakura—the real Sakura—is still on his mind.
After years of a pointed refusal not to think of her, not to consider her in any equation—he finds he cannot stop.
At this point, I'd just really like to see what the hell is going on in Sasuke's head, as it really can't be pretty.