Quest (1972)

Bored to death during her summer vacation at the luxurious Lagonisi Resort, Elena, the tanned, fabulously rich, and world-weary daughter of the successful shipowner, Leon Chrysos, whiles away the time snooping on her unknown and sexually active next-door neighbour. Intrigued by the irresistible playboy, before long, Elena discovers that the loud Casanova is the obnoxious cynic and haughty multimillionaire, Thanos Vergis, who prefers paying for sex. Then, one hot afternoon, Elena summons up the courage to switch places with a beautiful call-girl, bent on meeting in person Vergis, of course, incognito. However, when Vergis ends up being the prime suspect in an unsolved murder, Elena finds herself between a rock and a hard place. In the past, people have called Vergis many names; but, is he a killer?