A plot twist might be that Anko was once in love with someone else, and that person suddenly returns. Naruto would then have to compete not just with his own insecurities but also with this new rival. Or, it could be that Naruto's crush on Anko is part of a genjutsu placed on him by an unknown enemy. When he breaks free from the genjutsu, he has to re - evaluate his feelings for Anko, and Anko has to deal with the fact that Naruto's feelings were not entirely real at first.
One possible storyline could be that Anko tries to subtly show her feelings to Naruto. For example, she might start offering to train with him more often. She could also be protective of Naruto in dangerous situations, which Naruto might initially mistake for her just being a good comrade. As the story progresses, her crush could lead to some comical misunderstandings, like when she gets jealous of other girls around Naruto.
One possible plot twist could be that Anko is actually working undercover for an enemy organization all along. She got close to Naruto to gather information, but then truly fell in love with him during their relationship. Naruto would be devastated when he finds out and have to decide whether to trust her again or not.
One idea could be that Naruto tries to impress Anko with his new jutsu skills. He might show off in front of her during a training session. Since he has a crush, he'll be a bit clumsy about it but also very determined.
A possible plot twist could be that Naruto is oblivious to Sasuke's feelings at first. He might just think of her as a good friend and Sasuke has to work hard to make him see her in a different light.
Maybe Naruto discovers that his cancer is a key to unlocking some ancient power. So instead of it being just a death sentence, it becomes a journey of self - discovery and a way to become even stronger in a different sense. He could have to go on a quest to find the right knowledge to use this new - found connection.
If Naruto does figure it out, he could be really flattered. He might see Anko in a whole new light. But he would also be a bit confused because he has always seen her more as a senior or a friend. He would probably try to handle the situation gently, not wanting to hurt her feelings.
Well, a plot twist might be that Naruto discovers Anko has a hidden power that she's been suppressing. This power could be related to a rare bloodline or a forbidden jutsu. As they start dating, Naruto notices strange occurrences around Anko and eventually uncovers this secret. This could create a rift between them as Naruto might be worried about the implications of such a power, while Anko is afraid of being rejected because of it. Also, there could be a plot twist where the Akatsuki targets Anko because of her relationship with Naruto. They might see her as a way to get to Naruto and try to kidnap or manipulate her.
One possible plot twist could be that Anko has a hidden power that Naruto uncovers during the adoption process. Maybe she has a connection to an ancient clan or a special jutsu that she's been suppressing. This discovery could change Naruto's view of her and also put them in danger as others might be after that power.
Another plot could involve female Naruto's friends noticing her crush before she's ready to admit it. They might try to play matchmaker, which could lead to some awkward and funny moments. For instance, if her friends think she has a crush on Kakashi, they could set up situations where she has to be alone with him, like 'accidentally' leaving them together during a mission briefing. This would force female Naruto to deal with her feelings in unexpected ways.
One possible plot twist could be that Anko discovers the baby Naruto has some unique and unexpected powers right from birth. Maybe powers that are not shown in the original Naruto story. For example, he could have an instant connection to snakes like Anko, which could lead to a whole new arc in the fanfiction about him learning to control this power and how it affects his relationship with others in the Hidden Leaf Village.