He could be betrayed by a false friend in the DxD world who spreads lies about him. For instance, telling others that Naruto has a hidden agenda to take over their realm.
Naruto would likely be deeply hurt. He is a character who values friendship and loyalty highly. Being betrayed by someone he might have considered an ally like Rias would be a huge blow to his emotional state.
In a more complex scenario, Naruto could be influenced by an outside force. Let's say an enemy of Konoha uses mind - control or some form of manipulation on Naruto. They make him believe that the ANBU is the enemy of the village and that he needs to take them down. As he betrays the ANBU, he slowly starts to realize that he's been used, but by then he's already in too deep and has to find a way to fix the situation and regain the trust of his friends and the village.
In this fanfiction scenario, Naruto's betrayal by Akeno could be due to a misunderstanding of their goals. Maybe Akeno has been influenced by some dark forces that made her turn against Naruto. It could also be that there is some hidden information that led to this sudden change in their relationship.
In fanfiction, Naruto being betrayed by Akeno could be a very interesting plot twist. It might start with Akeno having some hidden motives or being forced by an external power to turn against Naruto. Maybe she was blackmailed into doing so. This could lead to a whole new set of adventures for Naruto as he tries to figure out why she betrayed him and also deal with the consequences of her actions.
Sasuke could also be a character who is frequently betrayed in these fanfictions. Given his complex personality and his history of being both a loner and a seeker of power, he might be lured into dangerous alliances in the DxD world. And his partners in the DxD world could betray him when they realize they can't control him or when his power becomes a threat to them.
Naruto would probably be extremely hurt. He has always considered Hinata a friend and perhaps more. Betrayal from her would be a huge blow to his trusting nature. He might initially be in denial, not wanting to believe that Hinata could do such a thing.
He could also feel angry. After all, he has fought for his friends and the village. To be betrayed by someone like Sirzechs would make him want to prove his innocence. He might start training even harder to show that he is not the bad guy Sirzechs is making him out to be. And he would likely try to find evidence to clear his name.
Naruto would be extremely hurt. He's a very emotional person who values friendship deeply. He'd probably first try to understand why Yugao did it. He might be in denial at first, thinking it's some kind of misunderstanding.