Grave Mercy by Robin LaFevers is another female assassin book. (It seems like I've read a lot of them in the past few years -- is this a Thing?)
Ismae Rienne is a daughter of Mortain, the god of death, and as such she is an object of fear and loathing to most of the people around her. When she is forced into an abusive arranged marriage, she escapes to a convent of other women who, like her, have been given special gifts by Mortain. At the convent, Ismae is trained in the art of death -- after three years, she can kill a person with sword, knife, crossbow, garrote, poison, or her bare hands. She can see a "marque" on those who are about to die, and for the sisters at the convent, murder is not a crime, but a holy calling. When Ismae is sent out on an assignment to the court of Anne, Duchess of Brittany, she finds that her tasks are not as clear and simple as she expected. Ismae accompanies Gavriel Duval, illegitimate half-brother to the duchess, presumably as his courtesan. Ismae is to discover who is truly supporting Anne, and who is secretly in league with the French. As she is caught up in courtly intrigue, she begins to question the decisions of her superiors at the convent. What will she do if she is instructed to kill someone she desperately wants to keep alive? Does the convent really represent Mortain, or are they serving their own ends?
There are a lot of things to like about this story -- the interesting medieval setting, the slow-burning romance between Ismae and Duval, and the complex political maneuverings of the court and the convent. Moreover, while this book is the first of a series, it wraps up most loose ends neatly, and I believe the next book will feature a different main character. The writing is on the good side of mediocre -- not fantastic, but definitely readable. I'll be on the lookout for the next book in the series.
(Reviewed from a copy borrowed through my library system.)