Answer and Explanation:
Let's divide that question into two so that we can answer it more easily.
Who is the hero or protagonist in Jorinda and Joringel?
The hero in the fairy tale is Joringel.
What actions define that character as the hero?
The hero in a fairy tale is often young, handsome, intelligent, strong, and brave. He is the one who defeats the antagonist, often a witch or a wizard who, for no reason whatsoever, enjoys imprisoning people and spreading evil. It is also common for the hero to have a special power or weapon that can help him destroy the antagonist and live happily ever after.
That is precisely why Joringel is the hero. He is a young, handsome man who happens to be in love. His fiancée, Jorinda, is taken by an evil witch. For some unexplainable reason, Joringel dreams of a flower that has the power to defeat the witch and bring back Jorinda. He finds that flower, defeats the awful witch, and lives happily ever after. As we can see, his fits the mold (beauty, courage, special weapon, victory, happiness).