Naruto could overcome the betrayal in this fanfic by reflecting on his ninja values. His belief in hard work, perseverance, and never giving up would help him. He could also try to forgive his friends in his heart, not for their sake but for his own peace of mind. He might then use the experience as a lesson to be more cautious in future relationships while still maintaining his open - hearted nature.
He might overcome the betrayal by focusing on his own growth. By becoming stronger both physically and mentally, he could rise above the pain of betrayal. He could also look back on the good times with his former friends and use that as a motivation to move forward and prove himself.
In such a fanfic, Naruto would likely be deeply hurt. His trust in his friends being shattered could lead to him becoming more isolated. He might start to question his own worth and his ninja way. Maybe he would turn away from Konoha for a while to figure things out on his own.
At first, Naruto might be in shock. He has always trusted his friends, so the sudden betrayal would be a huge blow. He could be silent, unable to process what has just happened.
Sasuke is a likely candidate in some fanfictions. Given their complex relationship throughout the original series, it's easy to imagine a scenario where Sasuke's thirst for power or some misinformation leads him to betray Naruto. Another could be Sakura. If she becomes jealous of Naruto's growing power or if she's manipulated by outside forces, she might turn against him.
Naruto could initially be shocked and hurt. Given his trusting nature, Akeno's betrayal would come as a big blow. He might go into a state of disbelief, trying to figure out why she would do such a thing.
It could be that they were misled. For example, they might have been tricked into believing that Naruto was a threat to the village in the future. So, in an attempt to safeguard the village they love, they decided to 'betray' Naruto. This would add a lot of complexity to the story as Naruto discovers the truth later.
It could be Zabuza. He might pretend to be on Naruto's side at first during the Wave events and then betray him when Naruto least expects it. Zabuza is a mercenary and his loyalty can be easily swayed.
Naruto might become more introverted. Without friends to interact with, he'd have to rely on himself more. He could develop a very independent streak, focusing on self - improvement in his ninja skills without the motivation of friendship. For example, he might train in solitude for long hours, becoming a very powerful but lonely ninja.
Sakura might be very worried. She's a medical ninja, so she would be concerned about the potential harm Naruto could be doing to himself. She'd probably try to stop him or at least monitor his experiments closely. Sasuke, on the other hand, might be more understanding in a way. He knows what it's like to push oneself for power, but he might also be a bit skeptical and warn Naruto about the risks.
Well, Naruto's friends' reactions would depend on their personalities. Sasuke, if he's around, might seem indifferent on the surface but secretly think that Naruto is being an idiot as usual. Hinata might be a bit shy about the whole situation, but also happy for Naruto if she senses that he really likes Temari. And Lee would probably be super excited and start shouting words of encouragement to Naruto, saying things like 'Go for it, Naruto! Show your youthfulness in this pursuit of love!'
One possible reason could be jealousy. Maybe Naruto has been getting more attention from the village elders or teachers because of his potential. His friends, feeling left out or overshadowed, might start to ignore him out of envy.