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.
In some fanfictions, Sakura's punch might be part of a comical situation. For example, Naruto says something really stupid and Sakura just can't help but punch him. But this punch then leads to a series of adventures as Naruto tries to get back at her in a friendly way.
I recommend 'The Punch that Changed Everything'. In this fanfiction, Sakura's punch makes Naruto see the error of his ways regarding a certain mission. It's a short but impactful read.
Well, Naruto would probably be in a great deal of pain. He might double over and be unable to move for a while. It could also lead to a big argument between him and Sakura, with Naruto feeling betrayed and Sakura perhaps realizing she overreacted.
In the fanfic, Sakura might be influenced by some dark force or a bad character. She starts to act against Naruto and their friends. Naruto, being the hero, tries to reason with her first but when she attacks him, he punches her back. This punch snaps her out of the influence, and they join forces again to fight the real enemy.
It would likely strain their relationship at first. Sakura would probably be very angry and hurt, both physically and emotionally. She might start to question Naruto's true nature and whether he really was the friend she thought he was.
Yes, there might be such fanfics out there. In the Naruto fandom, with a large number of fans creating various types of stories, it's possible that some would write a story where Naruto destroys Sasuke in a way that could be seen as Sasuke - bashing. However, these kinds of fanfics may not be in line with the overall spirit of the original work which focuses on their complex relationship and growth.
It could become more strained at first. Sakura would be hurt, both physically and emotionally, and she might hold a grudge against Naruto. However, if Naruto had a good reason for punching her, like protecting her from a greater danger she didn't see, she might eventually come to understand and their relationship could become stronger in the long run.
Perhaps there was some sort of dark influence at play. In the world of Naruto, there are often dark forces and genjutsu (illusion techniques). It's possible that Naruto was under the influence of a genjutsu that made him see Sakura as a threat, so he punched her in self - defense without realizing it was an illusion.
In the 'naruto is protected by sasuke fanfiction', Sasuke's protection of Naruto could be multi - faceted. Sasuke, being a powerful ninja, would first of all use his physical strength and speed to block attacks aimed at Naruto. Emotionally, his bond with Naruto would make him extremely vigilant. He might sense Naruto's distress from afar and rush to his aid. In terms of strategy, Sasuke would likely plan their movements carefully when they are in dangerous situations, ensuring Naruto is always in a relatively safe position. His ability to quickly analyze a battle situation and react accordingly would be crucial in protecting Naruto.