Hi! In the final game every love interest's route has two possible good endings. How your romance progresses and which ending you receive depends on role-playing choices you make throughout the route.
For instance, Will Scarlet is a daredevil. If you pick his route, you have to decide if you enjoy jumping into the danger zone with him or if you prefer to be a more strategic decision-maker. This will affect how your relationship develops and the challenges that the two of you will face as a couple, leading to different kinds of endings. Hope that helps!