Some tired boys(1967)

Overview:

Dinos Diamantidis, a good-looking, 50 years old, man who lives with his sister, is running behind any attractive female. When he meets the twenty-year-old Korina he loses his mind as Korina pretends that she is in love with him. His secretary, Rita, who has been engaged for many years with him, takes action and, with the help of his doctor and a former employee, makes Dinos finally figure out what this girl really is.