An Amphibious Swim
Following a river east, Rosella found herself by a giant waterfall and pool that were connected to the mountains. Perhaps this was where she would find the way to the magic fruit! Try as she might, though, she couldn't swim under the falls, for they were too powerful for her.
But then, she remembered the magic crown that the idiot said would turn her into a frog. Putting it on, she indeed did turn into a frog, and she was able to swim under the water and into a cave on the other side, where she turned back into herself.