One possible reason could be to escape the danger and chaos that might be brewing in England within the wizarding world. Maybe there are dark forces targeting them specifically, and leaving is their only option for safety.
One possible reason could be a shift in their loyalties. Maybe they discover some dark secrets about Harry or the side he represents that make them uncomfortable. For example, if they find out that Harry has some hidden motives that go against their own beliefs or values.
One possible reason could be a misunderstanding. Maybe they misinterpreted something Hermione said or did, and in a fit of anger or confusion, they decided to leave. For example, if Hermione was working on a project alone without consulting them, they might have felt left out and left in a huff.
One reason could be to explore the wizarding world outside of England. There are many magical places they might be interested in, like the wizarding communities in France or America. They could be on a mission to learn more about different magical cultures and bring back new knowledge to England.
One possible reason could be to protect Teddy. Maybe there are some threats in England that Harry wants to keep Teddy away from. For example, there could be some dark wizards or dangerous magical creatures that target Teddy for some reason.
One reason could be to find peace. After all the chaos and war in England, they might just want to get away from it all and start fresh somewhere else.
One possible reason could be to escape the danger in England. Given the dark forces that were at play, especially Voldemort's rise, they might have felt it was safer to leave. Another reason could be for a fresh start. Maybe they wanted to explore new magical cultures and communities in other parts of the world.
One possibility is that they leave England in search of a magical place that can offer them a peaceful life. They could be tired of the constant battles and power struggles in England. They might go to a far - off land where magic is used in a different, more harmonious way. For example, they could head to some hidden island where ancient magic thrives and they can study and grow without the interference of the Ministry or dark wizards.
It could be that Harry and Susan are escaping some sort of danger in England. They leave secretly and head to France. There, they try to blend in with the local community. Harry might find work as a painter and Susan could start teaching English. Their journey would be about not only starting anew but also constantly looking over their shoulders in case the danger from England follows them.
One possible reason could be that she feels she has outgrown the guild. Maybe she wants to explore new magic on her own and believes the Fairy Tail environment has become too comfortable and is hindering her growth.
One reason could be to seek a new life away from the political drama in Konoha. Naruto has always been in the spotlight and has faced many political challenges. Hinata, being by his side, might support his decision to leave for a quieter place. Maybe they want to raise their family in a more peaceful environment, away from the constant threat of enemies targeting Konoha.