The Winner's Curses

Kestrel is the daughter of a decorated Valorian general who helped conquer the Herrani nation when she was a child. Kestrel has no real military skills with weapons but she is a good strategist. She has no interest in joining the military and because of this she is expected to be a society lady and marry. One day she ends up at a slave auction and ends up buying a Herrani slave even though slave owning is against her personal values. And the story goes from there.
I liked this book, I didn't love it as much as I expected since most of the reviews I have seen have this as a 4 or 5 star book. I found this book enjoyable and a quick read. I really liked the writing style and the story but there were some issues I had with character development and really the length of this book. I really enjoy that Kestrel is a strong lady but isn't physically strong, I love that she thinks her way out of problems. However this causes also cause some issues because Kestrel is so smart at times and then the things that she doesn't see coming or choices she makes are frustrating. I really liked the Slave as a character and how conflicting he is at times. I like that he is really smart and can keep up with Kestrel, but Kestrel can best him at times. The side characters in this book though are not super developed or dimensional, and mostly there to make one of our main characters look smart or like a hero. This book doesn't have much fat in the story though that does present problems at times. I feel like this book needed another 50 to 100 pages to really flesh out a few things, and build the world and characters a bit more. The story wasn't bad without it but things would have flowed a bit better without it.
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This book is hard to categorize in regards to genre, which is slightly problematic as I want to make a star jar this year and I kinda need a genre. This book is a young adult romance set in a historical fantasy world with no magic system. Think balls, swords, and carriages. Has anyone read this? any ideas on genre?