Byoujaku na Akuyaku Reijou desu ga, Konyakusha ga Kahogo sugite Nigedashitai (Watashitachi Kenen no Naka deshita yo ne!?)

The protagonist, a corporate slave in her previous life, is reincarnated as the villainous young lady Fiona, living a leisurely, slow life...or so she thought. But Fiona's frail body is not even in the official character's character profile! Now I understand. Why was Fiona the villainous young lady in the game? She was so sick that she had no choice but to take it out on others...

If things continued like this, she wouldn't be able to live a leisurely, slow life! Fiona made changes to her lifestyle and attitude to improve her health. But as soon as her previously hostile fiancé, Lewis, found out about the situation, he became almost overprotective and doting on her!?

"Breaking off our engagement? There's no way I'd do something like that."
"From now on, you can ask me anything. I'll grant your wishes."
Wow, something's wrong! It's so sweet, unlike the original...!

(Source: Comic Walker, translated)