Sakura might be in shock. She probably couldn't believe that Sasuke, someone she cares about deeply, would try to kill her. So she could be frozen in place for a moment, unable to react immediately.
Sakura may also become more determined. Instead of being completely broken by Sasuke's actions, she could use this as a turning point. She might decide to become stronger herself, not only to protect herself from Sasuke in case he goes berserk again, but also to prove to him that she is not a weakling and that she can be an equal to him in some way.
She could also be filled with a mix of emotions like hurt and confusion. After the initial shock, she might start to question their relationship. Maybe she tries to talk to Sasuke, asking him why he did it, while at the same time trying to defend herself in case he makes another attempt.
Perhaps Sasuke was testing Sakura's loyalty or strength. He may have thought that if she couldn't withstand his aggression, she wasn't worthy of being in his life. Also, his own inner demons, like the hatred he carried from his past, could have flared up and led him to almost kill her without fully realizing what he was doing.
Sakura may initially be paralyzed by fear, but then her love for Sasuke and her own determination to survive could kick in. She might try to counter - attack in a non - lethal way, hoping to subdue Sasuke rather than harm him. She could also call out to their shared memories in an attempt to stop him from actually killing her.
One possible reason could be that Sasuke was under some kind of mind - control or dark influence at that moment. Maybe he was influenced by an enemy's jutsu that made him lose his sense of self and turn on Sakura.
She might be initially heartbroken. Sakura, being in love with Sasuke, would surely be deeply affected when he neglects her. She could become withdrawn herself, losing some of her usual cheerfulness.
Sakura would probably be initially very angry. She has strong feelings for Sasuke, but kidnapping is a very extreme act. So she would likely fight back, using her medical ninjutsu skills and combat abilities to try and escape.
Another reaction could be that Sakura tries to follow Sasuke. She believes that she can change his mind or that she can be of help to him. She might leave her own responsibilities behind for a while to chase after him, thinking that their bond is strong enough to overcome whatever is making Sasuke leave.
On the other hand, Sasuke could be very stoic about it on the surface but internally be in turmoil. He might start to analyze his own actions and whether he had missed any signs from Sakura. He could also be the type to immediately start thinking of ways to win Sakura back if he realizes he can't stand the thought of her with someone else.
It could be because of a dark power corrupting Sasuke. Maybe an ancient evil force takes over him and makes him see Sakura as an enemy. In some fanfics, this kind of external influence can completely change a character's actions. Also, it might be related to Sasuke's pursuit of power. If he believes Sakura is standing in the way of his ultimate power - seeking goal, he could be driven to kill her.
There could be. Fanfiction allows for a wide range of interpretations and alternate storylines. But it's a really extreme and disturbing concept considering the bonds that Naruto, Sakura, and Sasuke share in the official story. It would be a very different take on the characters, and most fans who love the original story would probably find it hard to accept.
He might be initially confused. Sasuke is not used to Sakura ignoring him as she has always been somewhat persistent in her attention towards him. So, he may be at a loss as to why she is suddenly acting this way.