Iron Wall Maiden

Milliana Pearl lived happily with her fiancé, Prince Julius, until she was accused of killing the king and sentenced to execution. In her last moments, an unknown voice offers her a chance to change her fate by living 1,000 lives. After meeting the conditions, Milliana returns to her original life. As she attempts to alter her past and save her loved ones, she uncovers hidden secrets and discovers that, to succeed, she must live without forming relationships, challenging her deepest desires.

(Source: Tapas)