One possible reason could be that Sasuke might have gone too far in his pursuit of power even after the war. He could have been a threat to the newfound peace in the ninja world, and Naruto, as the protector of peace, might have felt he had no other choice.
One idea could be that Naruto, Sasuke and Sakura are sent on a special mission during the war. Naruto might use his new Sage Mode techniques, Sasuke could show off his evolved Sharingan powers, and Sakura would be there to heal the injured and also fight with her super - strong punches. They could face a powerful enemy that requires all of their combined skills to defeat.
Their relationship could start with respect. Naruto has always respected Sasuke, and in this case, Fem Sasuke. After the war, they might start having conversations about their dreams for the future. This could lead to them spending more time together, like having dinners or just walking around the village. Eventually, they realize they have feelings for each other.
The relationship could begin with simple acts of kindness. Maybe Naruto helps Fem Sasuke deal with the trauma of the war. He offers her emotional support, which she has never really had before. This makes her open up to him, and from there, they start to develop a bond. As time passes, they realize that their bond is more than just friendship, and they fall in love while trying to create a better future for their world.
There are fanfictions where Naruto and Sasuke's relationship after the war is more of a mentor - student dynamic. Naruto, with his growth and new - found wisdom, could be teaching Sasuke about different aspects of life in the village. Sasuke, in turn, could be teaching Naruto some of the more esoteric ninja techniques he learned during his travels. This way, they are constantly learning from and growing with each other.
One great fem Naruto x Sasuke after - war fanfiction is 'A New Beginning'. It focuses on how Naruto, as a female in this version, and Sasuke deal with the post - war rebuilding. Their relationship is portrayed in a very nuanced way, with Naruto being the driving force in getting Sasuke to open up more to the village again.
A possible plot could be that a new and powerful enemy emerges, forcing Naruto, Sasuke and Sakura to put aside their differences and join the war effort. They start by gathering intelligence about the enemy's strength and weaknesses. Then, they plan their attacks accordingly. Naruto could be the vanguard, using his Rasengan and other powerful techniques. Sasuke would be right behind him, using his Sharingan to anticipate the enemy's moves. Sakura would stay in the rear, healing the wounded and providing support when needed.
In some fanfictions, Naruto and Sasuke become closer friends. They finally understand each other completely and work together to rebuild the Hidden Leaf. They often meet up and share their experiences, training the next generation side by side.
In fanfiction, they might embark on a journey to find the origin of chakra. This would take them to far - off places, facing various challenges like harsh terrains and powerful beasts. Along the way, they would meet different people with unique chakra - related abilities and learn more about the essence of being a ninja.
A 'Naruto x Fem Sasuke after the war' fanfiction could center around the idea of rebuilding. After the destruction of the war, both Naruto and Fem Sasuke are at the forefront of the reconstruction efforts in the Hidden Leaf. They work side by side to restore homes, train new shinobi, and revive the village's economy. As they do this, they start to see each other in a new light. Naruto admires Fem Sasuke's strength and determination, while Fem Sasuke is drawn to Naruto's unwavering optimism. Their relationship blossoms as they create a new and better future for their village and themselves.