This one is a tough book to categorize. It's technically sci-fi romance, but the storyline revolved around a world of assassins. The story did feature spaceships, other planets, and other races, but the main focus of the story shifted between the hero Nykyrian (and his tally of very detailed kills), and the woman Kiara that he was protecting. 
 Nykyrian is a scarred, lonely assassin who is cold and unwilling to get close to anyone. When he finds a hostage on a ship that his team was sent to destroy, he immediately feels drawn to the terrified princess that he rescued. She herself struggles to warm up to him because she has witnessed his murderous streak firsthand, but for some reason, she can't seem to completely push him away either. 
 Even though the book is long (500 pages plus), it was engaging the entire time. There was a lot of actual good plot/story in between the romance. I was sucked into the world of the assassins and never once got bored, even with multiple extensive fight scenes.