In this fanfiction, one possible way to trick the Sharingan user could be through psychological manipulation. The character could have planted false memories or ideas in the Sharingan user's mind. For example, by using some genjutsu - like techniques that are not easily detected by the Sharingan. He might have also faked his own chakra signature to make it seem like he was a different person or had different intentions. Another way could be by teaming up with other characters and creating a complex ruse that involved multiple layers of deception, so that the Sharingan user would be overwhelmed and unable to see through all the lies.
Maybe by creating false visual illusions. For example, using some basic ninja techniques like the Transformation Jutsu to disguise as someone important to the Sharingan user. This could make the Sharingan user misjudge the situation and fall into the trap.
It could be Sasuke. In many Naruto - related stories, Sasuke has the Sharingan and is often the target of others' tricks or manipulations due to his complex personality and his power.
In fanfiction, Naruto could get the Sharingan through a blood - related connection that is revealed later. For example, it could be discovered that he has some distant Uchiha ancestry that gets activated somehow. Maybe a powerful enemy's attack awakens this dormant Uchiha blood in him, and as a result, he develops the Sharingan. It could also be that a powerful sage or a new character uses their own unique powers to bestow the Sharingan upon Naruto for a specific purpose.
Sakura could be an unexpected character to have the Sharingan. It would completely change her character dynamics. She could use it to enhance her medical ninjutsu, seeing the internal body structure more clearly. Also, she could become a more formidable fighter, using Sharingan - based genjutsu to her advantage.
Naruto might adapt by first trying to understand the basic functions of the Sharingan. He could start with the simple ability to see chakra flow more clearly. Since he has always been perceptive about people's emotions, he could use the Sharingan to read the emotions of his enemies through their chakra, which would help him in battles.
His confidence might grow faster. Since the Sharingan gives an edge in combat, Naruto would likely win more battles early on, which would boost his self - esteem. He might also become more introspective as the Sharingan has some psychological aspects to it.
He could change in terms of his relationships too. His friends might be both in awe and a bit wary of this new power he has. Naruto himself might struggle with the newfound power, as it's not his natural ability. He might become more introverted as he tries to master it privately, not wanting to accidentally harm his friends with this new, potentially dangerous power.
A character with both Mokuton and Sharingan would be unique in terms of combat style. They could use the Sharingan to predict an opponent's moves and then quickly use the Mokuton to create barriers or offensive wooden constructs. For example, they could see an incoming attack with the Sharingan and immediately grow a wall of thick trees with the Mokuton to block it.
If Naruto had the Sharingan in fanfiction, it would likely lead to some interesting power - up scenarios. He could combine the power of the Sharingan with his own massive chakra reserves. This might make him an even more formidable opponent. His training would also take a new turn as he'd have to learn to control and master the Sharingan's abilities, like the different levels of the Sharingan and their unique powers.
Naruto would become more introspective. The Mangekyou Sharingan often comes with a heavy burden and dark secrets. He'd have to deal with the new powers and the potential corruption they bring. For example, he might start to question his own motives more often.
Naruto's confidence would likely increase significantly. Having such a powerful and unique ability would make him feel more capable of protecting his village and friends. He might become a bit more reserved at first, as he tries to understand and master the new power, but eventually, he would use it to be more assertive in battles and in diplomatic situations as well, knowing he has an ace up his sleeve.