Veiled Court by C.N. Crawford

Join the Trials. Fake a Romance. Kill the King.

Ex-assassin Syn Malleore hates kings. The last one poisoned her sister, leaving her to slowly die. Now that the monarchy has fallen, Syn can finally leave London and return to the Fey realm to search for a magic cure.
But the Fey nobility are already plotting to restore the monarchy. In a hidden court, aristocrats fight to the death in brutal trials to claim the throne.
Syn won’t let another tyrant rise. Disguised as a baroness, she infiltrates the trials as a spy. Her first goal: steal a sacred relic to save her sister. Her second: destroy the monarchy.
But the greatest danger is Rion du Lac, a lethally seductive warlord. When he discovers she’s an imposter, he forces her to pose as his lover to win the crowd’s favor.

If he exposes her secrets, she’ll burn for treason. And if she fails, a new tyrant will rise.