He could also be determined to find out why he was betrayed. Ash has a strong sense of justice. So he might start investigating, trying to figure out if there's some sort of misunderstanding or if someone is behind the betrayal, like a new villain in the new region. He would likely not give up easily on his friends, believing that there's a way to make things right again.
Ash would probably be really hurt at first. He's always been so trusting of his friends. He might go off on his own for a while to clear his head, like he did when he had a falling - out with some of his friends in the past.
Ash might also feel a sense of responsibility. He could think that he did something wrong to cause the betrayal. So he'd try to change himself in some way. Maybe he'd train harder with his Pokemon to show that he's worthy of their trust again. He'd also be more cautious about who he trusts in the new region from then on.
It could be his rivals. For instance, Tracey or Paul might see Ash's potential in the new region as a threat and decide to betray him. They could try to sabotage his battles by giving false tips to his opponents or stealing his battle strategies.
In such a fanfiction, the plot could involve Ash being betrayed by his long - time friends. Maybe they envy his success in the Pokemon world. For example, Gary could spread false rumors about Ash in the new region, causing the local trainers to distrust Ash. This would make Ash's journey in the new region much more difficult as he has to not only deal with new Pokemon and challenges but also regain his reputation.
Ash might be heartbroken at first. He'd feel a deep sense of loneliness and confusion.
Perhaps in this new region, Ash discovers a powerful new Pokemon that others want to control. His friends, fearing the power of this Pokemon, betray him to protect the region. They might think that Ash is being too reckless with this new discovery and that it could lead to destruction. It could also be that there's a prophecy in the new region that Ash is somehow involved in, and his friends misinterpret it and believe he's the cause of potential harm.
I think Ash would be angry as well as hurt. He's a passionate trainer and his friends mean a great deal to him. He might challenge May in a Pokémon battle, not to defeat her but to make her see how wrong her betrayal is. And during the battle, he would keep asking her to come back to their old friendship.
Ash would be extremely hurt. He's a very loyal person, and having someone he cares about like Lillie betray him would be a huge blow. He might initially go into denial, not believing that Lillie could do such a thing.
Ash would probably be devastated. He would feel like his world has been turned upside down. At first, he might not believe it and think it's all a big mistake. As the reality sinks in, he could start to isolate himself from others, even from his Pokemon for a while. However, his strong will would eventually kick in. He would use this as motivation to become stronger, not just in his Pokemon battles but also in his ability to face challenges alone, without relying on his so - called friends.
Some of his more loyal Pokemon might try to resist the change. For example, Pikachu could use electric shocks to try and jolt Ash back to his senses. Pikachu has a strong bond with Ash and would be very confused and sad about his decision to join Team Rocket.
Ash could get angry. He has a strong sense of justice, and he might feel that May has violated their friendship. He could challenge her, not in a violent way, but more in a way to get an explanation and to try to make her see the error of her ways. He would likely be determined to show her that what she did was wrong.
Ash would likely be shocked at first. He's so used to seeing the good in people, especially fellow trainers. But then he'd probably get angry and determined to set things right. He has a strong sense of justice, so he wouldn't let the betrayal go unpunished.