Mein Mann darf es nicht wissen (1940)

Sabine Senden is desperate – she's hopelessly in love with Willi Ulbrich, her mother's lodger. The only problem is, her mother doesn't like the man at all. She even wants to sue him for defamation, since he allegedly called her a "hooded crow" after he and his friends partied all night and kept her awake. Without telling her mother anything, Sabine and Willi secretly marry before the lengthy legal proceedings are even over. Of course, Sabine can't possibly introduce her husband to her mother; so she simply presents Erich, her friend Ulla's fiancé, as her husband.