She might be indifferent. Sakura could simply act like Sasuke is just another acquaintance. When she sees him, she doesn't show any special emotions, just a casual nod or a brief greeting.
In some fanfictions, Sakura may be determined to find Sasuke and bring him back. She could set out on her own journey, facing various challenges along the way, and growing both as a person and as a ninja in the process of trying to reunite with him.
Perhaps Sakura has grown and changed herself. She might have developed new interests and values that are no longer compatible with Sasuke's. In the fanfiction, she could have met new people who showed her a different kind of love and respect, making her question her feelings for Sasuke.
At first, Sasuke might start with small gestures. For instance, he could be more attentive to Sakura's presence, like looking at her more often or listening more closely when she speaks. This could gradually lead to more direct interactions, such as him starting conversations with her instead of the other way around.
Sakura could also try to stand up for herself. If she believes that Sasuke is being unfair in his anger, she may argue back. For instance, if Sasuke is angry because of a misunderstanding, Sakura might try to clarify the situation and prove her point.
She may initially be angry. Sakura is a proud and strong character. She could confront Sasuke and Ino, demanding an explanation. After that, she might decide to become even stronger, both in her ninja skills and her emotional resilience, to show Sasuke what he's missing.
In some fanfictions, Sakura's reaction could be more complex. She might be hurt not just physically but also emotionally. This could lead her to question her relationship with Sasuke and might cause her to make some big decisions, like whether to continue trying to reach out to him or to cut him off completely.
Sakura might be heartbroken. She's been in love with Sasuke for so long. She could initially go into denial, thinking it's just a temporary thing. Then she might get angry and vow to prove herself to Sasuke, perhaps by becoming an even stronger ninja.
She could be heartbroken. Sakura has always loved Sasuke deeply, so his leaving for Naruto would be a huge blow to her. She might initially be in denial, not believing that Sasuke would choose Naruto over her.
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 She could become withdrawn herself, losing some of her usual cheerfulness.
It could also be because of the fans' personal preferences. They may not like the idea of Sasuke and Sakura being together. So they create fanfictions where Sasuke doesn't love Sakura to satisfy their own vision of how the story could be. They might be fans of other pairings involving Sasuke or just don't think Sakura is a good match for him based on their understanding of the characters' personalities.