In ash and bonnie body swap fanfiction, Ash's personality is known for his tenacity in the Pokémon journey. When he swaps into Bonnie's body, he'll still have that underlying drive. He might be a bit more impatient with Bonnie's more laid - back activities. Bonnie is usually quite bubbly and friendly. In Ash's body, she could use her friendliness to make new allies in the Pokémon world. She might also be a bit more impulsive in battles compared to Ash, which could lead to some interesting and unexpected outcomes.
Ash is typically a very determined and adventurous character. So when he's in Bonnie's body, he might bring that sense of adventure into Bonnie's more ordinary daily life. For example, he could be more eager to explore new places around the town. Bonnie, on the other hand, is often curious and energetic. In Ash's body, she'd probably show a lot of enthusiasm for Pokémon battles and training, perhaps approaching it with a fresh perspective that Ash himself might not have considered before.