The Perfect Plan for a Fairy-Tale Ending

Once upon a time, poor little Larissa Blick was tortured by her greedy family for her diamond tears. She grows up and is rescued by a prince, leading to a beautiful fairy-tale ending—though not for her evil sister Marcia, who dies at the prince's hand. When a university student from the modern world is reborn as Marcia, she vows to prevent her own death while giving Larissa the happily ever after she deserves. With Marcia's powers and some modern-day insight, can this fairy tale be rewritten?