Heart of the Moon Goddess by Joline Lim (paperback)

A girl born with the power of the moon.
A prince gifted with the radiance of the sun.
And the rise of the sea king, the Bakunawa.

Luna has been haunted by the same dream for weeks-tortured by flames in an arena, accused of witchcraft, and saved by a mysterious figure. Raised in the House of Wives, she was groomed to become a future bride for royals and noblemen. But Luna harbors a secret: her heart glows like the moon.

During a sea voyage with the prince, Luna falls overboard and discovers an underwater cave. There, she encounters a man in chains who bears a striking resemblance to her dream's savior.

As Luna unravels the mystery of her dreams and her glowing heart, she must confront a destiny that could change everything.