Maybe in the fanfic, Sasuke has done something to betray Sakura's trust. For example, he might have left the village again without considering her feelings.
It could be that Sakura realizes Sasuke's personality flaws more deeply in the fanfic. His obsession with revenge or his cold attitude towards her might make her hate him. In the Naruto story, Sasuke has always been a bit of a lone wolf, and if this is exaggerated in the fanfic, it could lead to Sakura's hatred.
Perhaps in the fanfic, there are some misunderstandings between them that are not easily resolved. Sakura might misinterpret Sasuke's actions as being deliberately hurtful, like if he was wrongly accused of something and didn't defend himself well, leading Sakura to think poorly of him.
In such a fanfic, one possible reason could be Naruto's feeling of being left out. Maybe he sees Sakura's constant focus on Sasuke and feels neglected in their friendship triangle. Another reason might be jealousy. If Naruto has unrequited feelings for Sakura, seeing her love for Sasuke could turn to hatred over time.
One reason could be that in some fanfiction, the characterizations of Sasuke and Sakura might be off. Maybe Sasuke is portrayed as overly cruel to Sakura in a way that doesn't seem true to his character in the original series. Another reason could be that the storylines in these fanfictions are too clichéd, like always having Sasuke constantly reject Sakura in the same uninteresting ways.
One possible reason could be jealousy. Maybe in the fanfiction, Naruto feels overshadowed by Sasuke in Sakura's eyes, which leads to his hatred. Another reason might be that he perceives their relationship as a threat to his own bonds with them. For example, he could think that Sasuke and Sakura's closeness excludes him in some way.
Well, one possible reason could be that Sasuke's mistake might have put their team in great danger. For example, if his actions led to the enemy getting an upper hand during a battle, endangering not only his life but also those of his comrades like Sakura. Sakura, who values the safety of the team, would then resent Sasuke for his mistake.
In lemon fanfiction, the 'sakura hates sasuke' scenario can stem from various factors. One possibility is that Sasuke's past actions, such as his association with dark forces or his disregard for the safety of the village which Sakura holds dear, could make her resent him. Additionally, if in the fanfiction's world, Sasuke has made decisions that directly oppose Sakura's efforts to build a relationship or a peaceful environment, it would be understandable for her to hate him. For instance, if he undermines her medical work in the village or her attempts to bring the shinobi world together.
It could also be a misunderstanding. Perhaps Karin is misjudged by Sakura in the fanfic. Maybe Karin did something that was misinterpreted as malicious towards Sakura or someone she cares about, leading to the hatred.
A scenario could be that Sasuke blames Sakura for something that went wrong in his revenge plan. Maybe she unknowingly did something that set him back, and in his anger and single - minded focus on revenge, he starts to hate her. Another possibility is that in the fanfic world, there is a misunderstanding. Sakura is misinterpreted as being involved with someone who has wronged Sasuke, and this causes him to hate her without really knowing the truth.
One reason could be jealousy. If in the fanfic there's another character who Sasuke is close to, Sakura might be rude out of envy. Another reason could be that she feels betrayed by Sasuke in some way, like if he made a decision without considering her feelings. Also, it could be part of her own character development, starting off rude to show her flaws and then changing later.
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.
One possible reason could be Sasuke's focus on his revenge. His thirst for vengeance against Itachi might make him blind to Sakura's feelings and neglect her as he is constantly preoccupied with getting stronger to achieve his goal of revenge.