100-nichigo ni Shinu Akuyaku Reijou wa Mainichi ga Totemo Tanoshii.

The duke's daughter, Lelouche, receives a revelation from God: "You'll die in 100 days." There are rumors that her fiancé, the crown prince, has found another woman and is about to annul their engagement. ...Moreover, it seems that no matter what she does, Lelouche can't escape death. However, the circumstances and the method of her death can be changed. After being told that, Lelouche offers a bet to God. "If I can show you a beautiful death, I want you to reward me." "All right. In your next life, I will grant your wishes." '...Well, looks like I got my hands full,' thinks Lelouche. She can't leave that thieving cat as it is. She also has to do something about her withdrawn brother. She has to prepare something to support her parents. She has a lot of things to do...! In the end, she shall regret nothing...! Thus, a life where she made a bet with God begins. (Source: Shousetsuka ni Narou, translated)