Itsuwari no Ou no Omoi Hana

After the death of her parents, Peony prepares herself to join the nunnery, but one day she is discovered by the king and he takes her away to become his mistress. The king looks exactly like Peony's first love, Zack. However, the cheerful and outgoing Zack is nothing like the cold and taciturn king. Peony is unhappy because of the difference in their personalities, but the next time she meets the king, he tells her that he really is Zack! "I finally found you," as he showers her with with passionate kisses and sweet, tender caresses. He embraces her with the same passion as before, but Zack the king has a secret. The mysterious king who is willing to destroy everything to make his first love come true. (Source: EastPress, translated)