My Revenge On The Crimson Queen summary:

Read manga My Revenge on the Crimson Queen / Seijo wa Tsumi o Yurusanai / Elisa, the daughter of the count and a priestess-in-training, was devotedly working towards the betterment of her kingdom.Despite her humble and clumsy demeanor, she lived a life of contentment and peace, cherishing what she had. However, her world was shattered when her beloved older sister, Iris, who was dispatched to the palace as a consort candidate, was unjustly framed by the despotic Queen Paris, leading to the execution of their entire family.Rescued by Prince Luka from a neighboring kingdom, Elisa plunged into despair after losing her dear family. Overwhelmed by grief, she swore to avenge her family's death and unravel the truth behind Iris's alleged treason. Elisa then adopts a new identity as Elena Porshal, the daughter of Viscount Porshal.Haunted by the question, "Why did my family have to die?", Elena embarks on a mission to unveil the truth. She enters the castle as the king's latest consort candidate, determined to extract the truth directly from Queen Paris herself!