It starts out where the girl is given poison by sister that she takes. Then the male lead who is a knight turns back time but catch is he doesn’t have his memory of the future. She does and chooses him as a knight/escort or something which she didn’t do originally cause she didn’t like what it meant. She is a princess and her family is kinda evil.
Princess Evienrose, despite advocating fiercely for the rights of the homunculi rebels, now awaits death at their hands… that is until she is poisoned by her own sister! Awakening eight years in the past, Eve now has one goal: become the Empress and liberate the homunculi to stop the rebellion from ever happening! To do this, she appoints the rebel king himself, Mikaelis Agnito, as her personal knight. But with Eve’s scheming sisters standing in the way, the fight for the crown is on, and the fate of the Hadelamid empire rests in her hands!
I have not found a non-copyright-infringing site that has a section I can quote, but indeed Mikaelis can rewind time.
Found with a search for
manhua princess poisoned knight "time travel"