It could be that the character relationships in Itachi fanfiction are used as a model. For example, if there are complex relationships between Itachi and other characters in the fanfiction, similar complex relationships could be created for Sakura. This would involve things like having her interact with other characters in new ways, having rivalries or alliances that are inspired by those in the Itachi fanfiction, which in turn trains her character in different aspects such as her social skills or ability to deal with conflict within the fictional world.
One way could be through adopting the narrative styles often used in Itachi fanfiction. For instance, if those fanfictions tend to have a lot of internal monologues for characters, Sakura could be given more in - depth internal thoughts in a similar way.
It could mean that in a creative or fictional context, Sakura's character development or some aspect of her is being shaped or influenced by fan - created stories about Itachi. Maybe in these fanfictions, certain scenarios or interactions with Itachi are used to mold Sakura's character in new and different ways that deviate from the original canon.
Well, it could be about Itachi taking Sakura under his wing to train her in various ninja skills. Maybe he sees potential in her that others haven't noticed.
Perhaps Sakura gets into trouble during a training exercise and Itachi has to rescue her, which then leads to a more intense and focused training regime. Another development could be that Sakura starts to think like Itachi in battle situations, using his tactics to outwit her opponents. It could also be that as she gets stronger, other characters start to notice and either become jealous or try to recruit her for their own purposes.
Jealousy can be shown through actions. For instance, if Sakura is jealous, she might avoid Itachi. She could also be short - tempered when he tries to talk to her. Just like in real life, people who are jealous often act differently towards the person they're jealous about.
Sakura would probably be angry at herself for being captured. She's a proud ninja. So she would start looking for weaknesses in Itachi's hold on her. Maybe she would try to engage him in conversation to find out his motives, all the while formulating a plan to break free. She could also try to send out some sort of signal to her comrades if possible.
She probably changes in her mindset. Itachi's influence might make her think more strategically. Instead of just relying on brute force or basic medical ninjutsu, she could start to analyze situations better and come up with more effective solutions. For instance, she might learn from Itachi how to anticipate an opponent's moves based on their body language and chakra flow.
In this fanfiction, Itachi might help Sakura become stronger by training her in various ninja skills. He could teach her advanced genjutsu techniques. For example, he might start with the basics of detecting and breaking genjutsu, and then gradually move on to creating complex illusions herself. This would enhance Sakura's ability to defend against and use genjutsu in battles.
Naruto may become more calm and composed. Itachi's presence and training methods would likely instill a sense of discipline in Naruto. He'd probably be less impulsive in battles and think more before acting.
His possessiveness could be seen in his actions towards Sakura. He may be overly protective, like not allowing her to go on dangerous missions alone. He would always want to be the one to accompany her, ensuring her safety at all times. This shows that he doesn't want to share her with any potential threats that could come her way during a mission.
In this scenario, Sakura would be horrified. Her view of Itachi would turn from perhaps a neutral or even positive view (if she had any such view in the fanfiction world) to one of pure hatred. Their relationship would become one of enmity. Itachi using her as a shield would be a huge violation of trust and basic human decency, so she might even try to expose his actions to the other characters, causing a rift in the overall story's character dynamics.