The most important thing is that the seduction triangle functions on every part. Maurice Ronet (the man), Lisa Gastoni (the woman) and Graziella ("little grace" = Jenny Tamburi) are believable in their roles, with Gastoni really delivering a stunning performance, and Jenny Tamburi is, well, pretty and superficial. As she would be. It is a great twist that is at once the spurned woman but also a caring mother who worries about her daughter and just about a fellow woman suffering a broken heart.
In my opinion, this is not an Italian version of Lolita. Lolita the book is actually about the sexual exploitation of a girl. This is not the case here as Graziella is an active participant who is hopeful of getting one over her mother and thus emancipating herself.
NB the 15 years-old Graziella is played by the 21 years-old Tamburi.