Rutherford, Mara. Crown of coral and pearl (Series)

"Nor once dreamed of seeing the wondrous wealth and beauty of Ilara, the kingdom that's ruled her village for as long as anyone can remember. But when a childhood accident left her with a permanent scar, it became clear that her identical twin sister, Zadie, would likely be chosen to marry the Crown Prince--while Nor remained behind, unable to ever set foot on land. Then Zadie is gravely injured, and Nor is sent to Ilara in her place. To Nor's dismay, her future husband, Prince Ceren, is as forbidding and cold as his home--a castle carved into a mountain and devoid of sunlight. And as she grows closer to Ceren's brother, the charming Prince Talin, Nor uncovers startling truths about a failing royal bloodline, a murdered queen...and a plot to destroy the home she was once so eager to leave. In order to save her people, Nor must learn to negotiate the treacherous protocols of a court where lies reign and obsession rules. But discovering her own formidable strength may be the one move that costs her everything: the crown, Varenia and Zadie"--Amazon.com