The main characters are the hero and the maid. The hero is likely to be a person of great importance in the story's setting, perhaps a warrior or a leader. The maid, on the other hand, is someone in a more subservient position. But in a love story like this, their roles might start to shift as their relationship develops. Maybe the hero discovers that the maid is stronger in spirit than he initially thought, and the maid might find that the hero has a soft side that others don't see.
Obviously, the hero and the maid are the main characters. The hero could be a brave and noble figure, famous for his deeds. The maid might be an ordinary girl working in a big house or castle. Their relationship is the core of the story. As the hero proposes to the maid, we can assume that they have some special connection. It could be that the maid has been by the hero's side during difficult times, and he has come to realize her importance. There may also be other secondary characters who play roles in either supporting or opposing their relationship.
Based on the title, the two main characters are clearly the hero and the maid. However, without reading the novel, we can't know much more about their specific identities. They could be from a fantasy world where the hero has magical powers and the maid has some special skills or qualities that attracted the hero.