V.E Schwab 
Shades of Magic [PDF ebook] 
The Steel Prince #5

Having vanquished the Pirate Queen, Prince Maxim Maresh has now been tasked with commanding the Verose military barracks. However, the young, headstrong prince finds it hard to be accepted by the regular soldiers billeted there who see him as nothing more than a spoiled royal playing at being a soldier, and he yearns to earn their respect and be judged for his skills as a warrior and leader and not because of the privilege of his royal title.