Watashi ga Horobo Shite Ii desu yo ne - Junpaku no Seijo wa Fukushuu o Chikau

Summoned to another world as a Saintess, Sara believes her destiny is to save the Kingdom of Linus. With the encouragement of Prince Curtis and her friend Angelica, she gives her all to create a "Great Barrier" against the demons. But the ritual is a trap. The barrier demands her life as the price. Betrayed and murdered by those she trusted most, Sara's dying prayer to the goddess is not for salvation, but for a chance at revenge. Granted a second chance, she makes a pact with the enemy, the Demon King Yomudoit, vowing to tear down the kingdom with her own hands.

https://www.cmoa.jp/title/354224/