The Tunnel of Love (1958)

The Pooles are unable to have a baby after years of trying. They apply to the Rock-A-Bye Adoption Agency, and are assigned Miss Novick as an investigator. Through a far-fetched miscommunication, she gets a very bad impression of Augie Poole and indicates that her report will be unfavorable. Through even more far-fetched circumstances, Augie is able to change Miss Novick's mind, and later he comes to believe that the baby she is carrying is his. Rock-A-Bye does find the Pooles a baby, and Augie is convinced that it is Miss Novick's and he is the real father...so much so that his wife also comes to believe it. She threatens to leave him, but all the misunderstandings are finally cleared up for a happy ending.