Shiitagerareshi Reijou wa, Sekaiju no Aruji ni Narimashita

This is a Cinderella fantasy about an unlucky girl hiding strength and the power of destiny.

Despite being a count's daughter, Fiora is treated unreasonably. Her engagement broken, the sapling that was the last memento of her late mother gone up in flames, every day is spent suffering through this cruel treatment. However, one day, a strange yet beautiful man appears before her. His name is Arum. What's this about being the incarnation of Yggdrasil, and Fiora is now his master?

(Source: Kadokawa, translated)