Stormvalor (Stormborn Chronicles #1) by Starr Z Davies:
 
In the heart of a tournament, where legends are born and destinies forged, the fate of kingdoms hangs in the balance.

Aethan Starkling, a lord with dreams as vast as the realm itself, has long yearned to prove himself in the prestigious Stormvalor Tournament.

Aslyn Kiernan, destined to ascend the throne of Novavito, faces her own dangerous trials. An ambitious suitor from the Emperor's court schemes to force her into a marriage that would jeopardize her kingdom's future. Confronted with treachery, Aslyn must navigate the perils of the tournament to secure her destiny—or risk losing everything she holds dear.

As the tournament unfolds, Aethan & Aslyn's path intersect—pushed together by parents who seek a strong marriage match, and drawn together by the threads of fate. Together, they discover that strength and honor alone are not enough to secure victory. The price of winning is far higher than they ever imagined.

Bast Blackblade, a hardened assassin, lives by the edge of his lethal blades, dismissing the notions of gods and friendship. But when his final payment for a completed job vanishes, Bast embarks on a treacherous journey that leads him to the heart of Stormvalor, where he seeks to disrupt the budding romance between Aethan and Aslyn for his own purposes.

As alliances shift and secrets unravel, Aethan, Aslyn, and Bast must confront the truth of their own beliefs and the price they are willing to pay for victory... and for love.