Seiso Seijitsu ni Ikite Itara Konyakusha ni Uragirareta no de, Yarinaoshi no Sekai de wa Akuyaku Reijou to Shite Ikimasu

There's no such thing as sincere love... Mianna Caroline was raised strictly as a light mage user from a young age. After her mother passed away, her father remarried and adored her stepsister, ignoring Mianna. Then, to make matters worse, her fiancé broke off their engagement, saying he wanted to marry her stepsister instead. Mianna always believed that living honestly would be rewarded, but this betrayal makes her fall into using "dark magic" that humans aren't supposed to have access to. But in the next moment, she wakes up to find herself returned to the day she was born! Then, God tells her, "I'll give you a second chance." With a fresh start, Miana's journey to find love and heal her heart begins again...