Style, tone, and quality-wise of the plot and characters, this feels like a blend between "the Divorced Empress" and "I don't love you anymore."

Our MC, Ersia, is the calm and placid type, who expresses her love through devoting herself to becoming the best helpmeet possible and maintaining her dignity at all times. She is very much like a young Navier who hasn't fully grown into her grace and aptitude. The Crown Prince similarly reminds me of Sovieshu, though not nearly as bad (so far), in that he does actually love her, but won't show it unless she does it first, and that he tends to make significant plans without involving or informing her.

This early on, it seems like misunderstanding will be the main source of plot fuel. Ersia is hurt that her one and only companion, the person she felt destined to be with, gave her up so quickly, and shuts off all of her feelings, slamming down the iron curtain. The Crown Prince takes her stoicism as a sign she never loved him, though he tries to probe further to discover if she has feelings, and is bound by the words of the prophecy.

I normally hate misunderstandings of this type, and yet it manages to work well here and keep me interested.

The most interesting thing is the prophecy and its effect on the story. I'm not sure how I'd like it to turn out.

Perhaps Ersia is the True Empress, who has been booted from her spot by a fake. But, the wedding is coming up fast. I can't see her being able to pull off the other aspects of the prophecy (curing 10, 000 people and stopping a war with a word) before the Crown Prince has to marry the fake. It would probably take years for her to prove herself, have them oust the fake, and get back together with her original fiance-- and all she'd win is a 2nd hand husband who didn't fight for her at the beginning, which would have avoided the heartbreak and mess, and the job of ruling a selfish kingdom which treated her like crap.

Or, maybe Ersia isn't the prophesied Empress, and that horrible other girl they've (successfully) been trying to make us hate is. Which means her ex gets to move on with few to no regrets, fall madly in love with this new girl, and rule supremely with her at his side as she goes on and does amazing feats that will get her name recorded in the annals of history. Ersia will have to find a new role and purpose in life, while watching all of that. Which leaves a bad taste in one's mouth, even if that's very realistic and she'll eventually wind up ok and in a place that's better for her.

An unlikely 3rd option would be neither Ersia nor the horrible new girl being the prophesied Empress, and a 3rd pink haired girl will pop in, which I would view as acceptable.

I like that I don't know and will need to keep guessing.