The Do-Over Damsel Conquers the Dragon Emperor, Vol. 1 (manga)

Although Jill's engagement to the Crown Prince should have guaranteed her a happy life, she is instead sentenced to death by her very fiancé! However, moments before her death, she is sent back in time to the party that determined her fate. In a desperate bid to avoid her doom, she proposes to the man behind her, but that man turns out to be none other than an enemy from a neighboring country, the Dragon Emperor, Hades!