Assassin & Cinderella

Neneko is a spy with a mission: to uncover the secrets of an assassin from a rival organization. Sadly, she blows her cover. But, just when she thinks she's about to be killed, the assassin proposes to her instead?! Caught within his lethal embrace, her heart slowly begins to melt... And so begins the story of the sweetest and deadliest couple in the world!

(Source: Manga UP!)