Based on the information provided, I'd say Fernessa would be a good fit for Gryffindor house. Here's why:
Bravery and courage: Fernessa is a brave and courageous character. She leaves her home in the Faewild to explore the Material Plane, even though she knows it will be dangerous. She also stands up for what she believes in, even when it means putting herself at risk.
Chivalry and honor: Fernessa is a chivalrous character who always tries to do the right thing. She is also very honorable and would never betray someone's trust.
Daring and nerve: Fernessa is a daring character who is not afraid to take risks. She is always up for a challenge and is not afraid to get into trouble.
Leadership: Fernessa is a natural leader who can inspire others to follow her. She is also very good at making decisions and solving problems.
Of course, there are other Harry Potter houses that Fernessa could also fit into. For example, she could be a good fit for Ravenclaw house because she is intelligent and curious. She could also be a good fit for Hufflepuff house because she is loyal and hardworking. However, I believe that Gryffindor house is the best fit for Fernessa because her bravery, courage, and chivalry are her most defining traits.
Ultimately, the decision of which Harry Potter house Fernessa belongs to is up to you. However, I hope that I have provided you with some information that will help you make your decision.
I hope this helps!