The Mischief-Makers (1963)

Thanasis and Vasilis, perpetually unemployed best friends, are in desperate need of money and a job. One day, chivalrous Thanasis saves Marina, a beautiful young woman in distress, and falls madly in love with her, unbeknownst to him, however, that she is Vasilis' sister. Now, as the budding romance turns into something more serious, Vasilis' is starting to suspect that his sister is having an affair. Will he accept Thanasis as his brother-in-law?