On the other hand, if he has moved on completely, he could be polite but distant. He would listen to what she has to say but make it clear that his life has moved in a different direction and he is no longer interested in rekindling anything.
Most likely, the character would be very confused. They would wonder what had happened and might immediately start trying to think of ways to reverse the situation. They could also be a bit scared, especially if they don't understand what's going on. For example, if they were used to having a male body and all of a sudden have a female body, they might be worried about how to act and how others will react to them.
Well, she might come back to seek closure. Maybe there were unresolved issues between her and the protagonist in the past, like an argument that ended their relationship abruptly. And now she wants to talk it out, to finally have a sense of peace about what happened.
Clint Barton would first and foremost ensure her safety. He'd take her into the house and get his family to help if possible. He'd call in any favors or use his old SHIELD connections to get medical help if needed. He'd be on high alert, knowing that if someone was able to injure Black Widow, they might be able to track her to the farm. His reaction would be a mix of loyalty to his friend and the need to protect his home and loved ones.
She might be initially shocked and confused. She would probably look at her new body in disbelief, trying to figure out what had happened.
Naruto would probably be initially shocked. He's a very loyal person, so he'd have a hard time believing it at first. Then he'd likely be very angry. He has a temper when it comes to things that are unjust, and this would be a huge betrayal. He might also feel really sad and disappointed in himself for not seeing the signs earlier.
Some people might immediately side with the girl, especially if they find out the boy was in the wrong first. For example, if he was the one who started the trouble by being aggressive.
Most people would be shocked and confused. It's not something that is expected in a normal relationship.
First, take a deep breath and try to stay calm. If it makes you uncomfortable, be honest and tell her. You could say something like 'I'm not okay with this story, it makes me feel uneasy.'
Listen to their explanation. There could be an underlying reason for why they made up the story. Maybe they were feeling lonely and wanted attention. Understanding their motivation can help you respond appropriately.
There would likely be shock and confusion. People around her would be at a loss for how to handle such a situation. Her family and friends might initially be in denial, thinking it's some sort of prank or a medical misdiagnosis.