This was a marriage proposal to repay a debt of gratitude.

This was an engagement born from gratitude. Forte, the only daughter of a poor baron family, receives a skill. While it's a skill that humans across the continent possess, her skill is one that allows her to save someone other than herself—but only once. She thought she would use it on family or friends. But for certain reasons, she ends up activating the skill on a stranger instead. The family of the person she saved is grateful to her, and she becomes engaged to that person. In other words, an engagement born from gratitude. ※Convenient logic. Loose and fluffy setting.