Waiting for You by Megan Derr

Shanna has spent her whole life waiting—waiting to be old enough, waiting for the day she must pick a consort, waiting for a chance to finally overcome her despicable stepfather… and waiting for someone to finally banish the loneliness that comes with being a queen-in-waiting one step away from being murdered.

On the eve of the two-week event during which she must pick a consort from a bevy of suitors, two strangers arrive claiming to have been invited—though she knows full well they did not receive any such invitation. But the handsome, mischievous Prince Kallaar is too intriguing to resist, and his quiet bodyguard too compelling to ignore…

But she’s learned the hard way never to let anyone get too close, and on the verge of gaining true independence her stepfather will stop at nothing to see she never gets it.