How Could a Bad Girl become Protagonist in a story?

It happens after Mirae finished reading the novel called "Innocent Girl in a Cruel World" that was about an innocent girl living in the wealthiest kingdom in the region called Arizona. But, she is forced to marry count from the north as political marriage. However, Sam, the male main lead was falling in love with Mirae since they were children. He is the count prince from the same kingdom whose elder would be marrying her. Soon, Anastasia, the antagonist of the story, is arranged to marry Sam. They were to preserve their purity until the end. Sadly, the ending was not as happy as expected. The love birds were killed by their spouses. Not long afterwards, the dirt business of Mirae was revealed by the police. She managed to escape, but "dor" she just died. And wake up in her new life as Mirae, the protagonist character in the novel she read last time before death.