I'll Marry Him!(2020)

As the illegitimate daughter of Duke McKellion, Lilian was never fully embraced by her father or society. So, when she has the opportunity to take her sister’s place in an arranged marriage to Emperor Kael Lu Kaldorf, Lilian jumps at the chance. The only problem is, her prospective partner gets cranky without his sleep, and since being cursed by a vindictive witch, the tyrannical emperor hasn’t experienced a single moment of slumber. But that’s no challenge for Lilian, who possesses the ability to induce sleep with a kiss. Now, tasked with the duty of keeping His Majesty well-rested, Lilian must kiss the emperor each night to keep his temper at bay. It’s a simple contractual agreement, and Lilian has no plans to develop romantic feelings, but what happens when Kael unexpectedly falls for her?

(Source: Tappytoon)