Jealousy or misunderstandings can also play a role. Maybe Sasuke sees Sakura getting too close to another character, like Naruto, and out of jealousy, he lashes out at her. Or there could be a misunderstanding where he misinterprets Sakura's actions as betrayal, causing him to hurt her either physically or emotionally.
One common reason could be Sasuke's thirst for revenge. His single - minded focus on getting stronger and avenging his clan might make him overlook Sakura's feelings and accidentally hurt her. For example, he might leave her behind in a dangerous situation while chasing after an enemy related to his clan's massacre.
A common reason is battles. Sasuke is often involved in intense combat situations in fanfiction, whether it's against old foes with new powers or entirely new enemies. His determination to prove himself or protect something often leads him to take risks that result in getting hurt.
One common theme could be the strain on their relationship. In some fanfictions, Sasuke's past traumas might cause him to unintentionally hurt Sakura emotionally. For example, his obsession with revenge could make him push her away. Another theme could be external threats that lead to them getting hurt. Maybe an enemy targets Sakura to get to Sasuke, and in the process, both of them suffer both physically and mentally. Also, misunderstandings play a big part. Sasuke's aloof nature might be misinterpreted by Sakura, leading to hurt feelings on her part.
One common reason is miscommunication. If Sakura misunderstands Naruto's intentions, she might react harshly and physically harm him. For instance, if Naruto tries to keep a secret from her to protect her, but she misinterprets it as betrayal.
It could be due to Sakura's feelings for Sasuke. If she's overly focused on Sasuke and Naruto gets in the way of her plans regarding Sasuke in some way, she might lash out and hurt Naruto without really meaning to cause serious harm.
In some fanfictions, Sasuke could be under the influence of some dark power or curse. This power might compel him to kidnap Sakura. For example, a dark entity might want to use Sakura's abilities or her connection to Sasuke for its own evil purposes, and Sasuke, being unable to fully control himself, follows its commands.
Protectiveness. Sasuke has seen a lot of danger in his life. He knows Sakura is a valuable person, both as a friend and as someone he cares about. So his possessiveness could stem from his desire to keep her out of harm's way. He doesn't want any bad guys to get near her.
One possible reason could be Sasuke's pursuit of power. In many fanfictions, his thirst for greater strength might lead him to leave Sakura behind as he embarks on a solo journey to train in more dangerous and secluded places. He may feel that his goals are too dangerous for her to be involved with.
One possible reason could be a lack of communication. If Sasuke is always away on his missions and doesn't share his thoughts and feelings with Sakura, it can create a rift. Another reason might be differences in their long - term goals. For example, Sakura may want a more stable family life, while Sasuke is still too focused on his pursuit of power or justice in the shinobi world.
One possible reason could be that Sasuke is frustrated with Sakura constantly trying to get close to him when he's focused on his revenge. He might yell at her to keep her away and not interfere with his plans.
One possible reason could be Sasuke's continuous absence. He is often away on missions, leaving Sakura feeling lonely and neglected. In fanfiction, this could be exaggerated to a point where she can't take it anymore.