A Shadow in the Ember by Jennifer L. Armentrout — book slip

Seraphena Mierel was chosen before birth to fulfill a desperate bargain made by her ancestor.

Her destiny is to become the Consort of the Primal of Death, but her true mission is to make him fall in love with her and then destroy him to save her kingdom from the Rot.

As an assassin, Sera is prepared for her task, but the Primal's unexpected kindness and seductive touch ignite feelings she never anticipated.

Torn between duty and desire, Sera must navigate a world of gods and secrets, where her life is forfeit either way.

First in the Flesh and Fire series, set in the Blood and Ash universe.