If you're looking for manga similar to Can't Lose You, you might like these titles. All recommendations are made by Anime-Planet users like you!
In addition to both being manhwa, they have a pretty similar feel - a girl must act as a boy and also a badass fighter, with plenty of danger in the way. Beyond that the stories aren't very similar, but I do think fans of one would appreciate the other.
Both put a huge accent on the pain, suffering and struggle the girls must go through in order to get their happily ever after. During the trails both girls are willing to sacrifice themselves(numerous times) for their loved ones but the stubborn prince charming never gives up their undying love.
He’s the ruler of the country of Roinne; she’s a typical Korean teen, and his 100% perfect girl. For the rich and powerful Jarte, he wants nothing more than to take this girl, Jay, for his own, and together the two begin a tentative, tender relationship. However, Jay and Jarte’s lives will be nothing but simple, as insecurities, assassins and rivals in love stand in the way! Will the two manage to stay happy together?
It's unsurprising that these two manhwa have a similar feel, given they're written by the same creator. While dealing with different subjects, they share a variety of plot points - a girl is thrust into a life of danger and intrigue, while falling in love with a beautiful boy. With an uncanny similarity in appearance, flow and feel, if you liked one you should probably check out the other.