Hi,
What does the underlined red phrase mean?
This movie has much that one would expect to enjoy, not the least of which is the lovely Jane Doe. Many things about it are good, and all the performances are quite strong (again, including Ms. Jane's).
It means that Jane is not the least enjoyable aspect of the movie. There are other parts that are less enjoyable.
By saying that she is not the worst, the writer actually is suggesting that she is one of the best aspects of the movie. He actually says this more clearly at the end of the next sentence, doesn't he?
Clive