Sure. In fanfiction, the relationship between Sakura and Naruto can be played around with a lot. Sakura's admiration for Naruto can be shown more prominently, making her seem like a fangirl. For example, she might be written to always be in awe of Naruto's new jutsu or his heroic deeds more than in the official story. It gives writers a chance to delve deeper into her feelings for Naruto in a different light.
Yes, there are likely to be such fanfictions. In the Naruto series, Sakura can be quite assertive and strong - willed. Her temper and skills could potentially be a source of intimidation for Naruto in the creative interpretations of fanfiction writers.
It could be Sasuke. If Sasuke has some sort of newfound connection with Naruto and it causes Naruto to shift his focus away from Sakura, then Sasuke would be the cause. For example, if Sasuke and Naruto team up for a powerful mission and their bond deepens in a way that makes Naruto neglect his relationship with Sakura.
One possible reason could be for the sake of creating a more complex love triangle in fanfiction. Maybe the writer wants to explore a different dynamic where Naruto and Hinata's relationship is strengthened by having a common dislike for Sakura. It could also be that the fanfiction writer is trying to give Hinata more agency and make her a stronger character by having her oppose Sakura in some way, perhaps in matters related to Naruto's affections.
One interesting storyline could be Sakura joining the Anbu and having to prove herself among the male - dominated group. She might face challenges like secrecy requirements and intense training, all while Naruto is on his own journey, and their paths cross in unexpected ways during missions.
On Naruto's side, he would probably feel guilty after realizing what he had done. This guilt could make him try to make amends, but Sakura's initial reaction of anger and hurt would still be a big obstacle in their relationship. Their interactions would be filled with tension and awkwardness.
She might be heartbroken. Sakura could initially be in shock and then fall into a deep sadness. She may blame herself for Naruto's leaving, thinking that she could have done something differently.
Sakura might be completely shocked at first. She might freeze for a moment, not believing what's happening. Then she could start crying tears of joy and say yes immediately.
It might be about Naruto living freely in a sense that he can make his own choices regarding his relationships. For example, he could choose his friends and allies more freely without political interference. In this fanfiction, he might not be bound by the traditional shinobi rules and hierarchies, allowing him to interact with different clans and villages on his own terms.
He could also interact with the scientists on Pandora. They might be interested in Naruto's abilities and study him. Naruto could in turn learn about their technology, which is so different from what he has in his own world. He might even help them solve some problems they have on Pandora using his ninja wisdom.