La svergognata.

In this movie a writer comes to stay at an island resort and gets involved with a teenage lolita who is there with her parents and rather malicious best friend. She teases the older man mercilessly--going to a hotel and dancing with him naked and then suddenly getting dressed and running off to a party with a young American guy. But it's not so much because she is malicious, but because she is really an insecure virgin. Finally, he gives up on her after his beautiful wife (Barbara Bouchet) shows up. But the younger woman becomes jealous and is not going to give up so easily. . .