There's no other guy for my girl. I might have someone flirt with her and her run from the idea, but that's about it.

There's a potential fiance for her guy, though he is NOT a fan of the idea in the least.

Basically, he's a prince and she's a nobody, but due to politics and religion, she's suddenly elevated to be a potential queen. A lot of that is the prince rebelling against what's expected of him and being so drawn to her in general (perhaps at first because of all the expectations weighing on him). She's naturally a bit uncertain what a romance with him would entail, especially with civil war looming (wouldn't want to be queen when the peasants revolt, after all!). But, they can't deny their feelings, he goes to bat for their relationship and just as it seems like a clear path everything falls apart and they're separated for more or less the rest of the book, each waging their own battle (he's dealing with a rebellion in his kingdom and she's in search of answers to save the world from destruction) until they are finally brought back together for the climactic ending.