First of all, read the amazing series by C.S. Pacat:

• Captive Prince - Volume 1
• Captive Prince - Volume 2
• Kings Rising - Volume 3

Then read these equally amazing and high quality fanfictions:

• Kings Reign http://archiveofourown.org/works/6100126
• One the Other http://archiveofourown.org/works/6354688
• The Heir http://archiveofourown.org/works/7284691
• Four sevens and a ten http://archiveofourown.org/works/6478726
• Lines on Palms http://archiveofourown.org/works/1099229
• Games of Chance (Pt. 2 of Lines on Palms) http://archiveofourown.org/works/5823553
• Marks of Fate (pt. 3 of Lines on Palms) http://archiveofourown.org/works/6113579
• Dear Aledosia http://archiveofourown.org/works/6251410
• The Viper among the Wolves http://archiveofourown.org/works/2237988
• Size King http://archiveofourown.org/works/7134629
• Wines and Flowers http://archiveofourown.org/works/6403321
• Once Bitten, Never Shy http://archiveofourown.org/works/6315367
• Along for the Ride (ongoing) http://archiveofourown.org/works/7586518
• Those Who Speak with Wild Beasts (ongoing) http://archiveofourown.org/works/7061515
• The Prince and the Beekeeper http://archiveofourown.org/works/1373620
• Sonnets of the Heart http://archiveofourown.org/works/6196663