Jishou Akuyaku Reijou na Kon'yakusha no Kansatsu Kiroku.

Synopsis:

Because Prince Cecil is exceptionally intelligent, he finds life dull and uneventful. His days lack excitement—until he becomes engaged to Bertia, the marquis’s daughter. Their first meeting leaves him completely confused when she boldly declares that she is the “villainous heroine” of his life story. Bertia claims to retain memories from a past life, where she played the role of a villainess in a romance game. In this new life, she is determined to fulfill that role perfectly by sabotaging the prince’s engagement. To carry out her plan, Bertia repeatedly acts in outrageous and unpredictable ways, throwing Cecil’s once-orderly life into chaos. Thus begins an unconventional love story full of surprises and unexpected twists.