She smiled the credulous smile of ignorant innocence and pulled the gate open.
As for the necklace, I will pay for it myself, and so pay for my credulous folly.
The spy was devout to the point of bigoted, credulous superstition.
Madame de Montespan was as credulous as only the very devout can be.
Then, sternly: "Think you I came here to play the credulous husband?"