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.
Sakura might be a bit surprised at first. But she would probably be happy for Naruto as long as he is happy. She might also be curious about the elf and want to learn more about her. Sasuke would likely be more reserved in his reaction. He might not show much emotion on the surface but deep down he would be glad that Naruto has found someone. Kakashi would probably give Naruto some sage advice about making a relationship work, especially since it's with someone from a different species.
His friends from Team 7, like Kakashi, would feel responsible for Naruto's situation. Kakashi would likely use his resources to find a proper shelter for Naruto. Shikamaru and the others might come together to form a sort of support group for Naruto. They would pool their resources, like money and food, and also try to cheer him up by sharing stories and jokes.
His friends like Kakashi would be cautious yet supportive. Kakashi would likely give Naruto advice on how to handle the relationship and the responsibilities that come with it. In Kirigakure, Mei's comrades might initially be distrustful of Naruto, but as they see his good intentions and how he treats Mei, they would gradually accept him. And Naruto's friends from other villages he has befriended over the years would see it as a positive step towards a more unified ninja world.
Kakashi would be more of a supportive figure. He has seen Naruto and Sakura grow up, and he would likely be happy for them. He might offer some advice to Naruto on how to handle this new relationship, especially considering the challenges they might face as ninjas. For Sakura, he could give her words of encouragement to be true to her feelings.
Sasuke might initially be a bit aloof but secretly be happy for them. He's always had a complex relationship with Naruto and Sakura, and deep down, he would see that they are good for each other.
Sakura might be extremely angry and feel guilty for not being able to protect Naruto. She could immediately start planning ways to rescue him and make Danzo pay for what he's done.
If Naruto gets captured by Orochimaru in fanfiction, his friends' reactions would be intense. Hinata, who has deep feelings for Naruto, would be heartbroken but also very determined. She might try to secretly track Orochimaru on her own at first, using her Byakugan to search for Naruto. Kiba with Akamaru would be eager to jump into action, using their tracking skills. Lee would be excited to prove his strength and save Naruto, ready to use his Taijutsu skills against Orochimaru. His friends' combined efforts would be focused on rescuing Naruto from Orochimaru's clutches as soon as possible.
At first, Naruto would be in disbelief. He has always trusted his friends wholeheartedly, so this would be a huge blow. He might then feel a deep sense of anger and sadness. However, Naruto being Naruto, he would likely also start to look for ways to prove his innocence or the misunderstanding. He might go on a journey of self - discovery to figure out what went wrong and how he can win back his friends' trust, all while dealing with the pain of the betrayal.