Rebel of the Sands by Alwyn Hamilton

Teen Amani lives with her aunt, uncle, and numerous cousins, helping to run the family store in Dustwalk. Amani sneaks out one night to win money in a sharpshooting contest. The next day she hides fellow sharpshooter Jin from the Sultan’s army. A train ride to the capital city ends abruptly, sending Amani, who is disguised as a boy, and handsome Jin on the run in the desert, which is full of danger and adventure. Amani reluctantly gets involved in a rebellion against the sultan, and meets people with various magical powers, half human and half djinni. Amani finds that she can’t tell a lie, and has to make choices about where her loyalty lies. This is a fun fantasy adventure that mixes elements of westerns with Arabian Nights.
Brenda