Old Dreams and Unspoken Feelings in the Seams of Time

This One Looks Good and Sounds Good. It’s a Brand-New Book

I want something similar to The Spirit Sakura Valley and the City of Eternal Night: Love and Salvation. A princess and a duke becoming a couple, along with adventure and challenges, a mysterious figure wielding dark power, a mission, their love story and relationship, and a marriage alliance between two countries.