Seijo ni Uso wa Tsuujinai

Chloe, a money-loving teenager who works as an apprentice priestess in a far-flung church, uses her memory and intelligence as weapons to gamble at cards and earn a lot of money at night. A wealthy holy knight named Erald pays her a visit and urges her to enter the church as a candidate for sainthood in order to track down the killer who killed someone two years prior.