Flame in the Mist by Renée Ahdieh

The only daughter of a prominent samurai, Mariko has always known she’d been raised for one purpose and one purpose only: to marry. Never mind her cunning, which rivals that of her twin brother, Kenshin, or her skills as an accomplished alchemist. Since Mariko was not born a boy, her fate was sealed the moment she drew her first breath.

So, at just seventeen years old, Mariko is sent to the imperial palace to meet her betrothed, a man she did not choose, for the very first time. But the journey is cut short when Mariko’s convoy is viciously attacked by the Black Clan, a dangerous group of bandits who’ve been hired to kill Mariko before she reaches the palace… Read more.