The evidence for this is that she's nice to old ladies and treasures a locket with a picture of her dead parents. That's about it for character development. However, the first 85 minutes are just a warm-up for the ending, which is as anticlimactic as it is profoundly dissatisfying. I can't imagine anyone, no matter what they thought of the movie as a whole, liking this conclusion. Either there was some serious last-minute editing or someone left out a few pages of the script.
Viewers invest something in every movie they watch, no matter how good or bad it is.
Cheating them like this is offensive and unpardonable. Films like Consenting Adults, The Hand that Rocks the Cradle , and Single White Female rely on stock plots and predictable twists to propel the narrative along. In general, however, they're directed with a degree of competence that assures a level of sustained tension. Indeed, the title of this movie probably refers to what the producers hope viewers will do in lieu of telling their friends what they really think of this sorry piece of celluloid.