Not to be sneezed at means that the rates are not to be ignored, and here in context the rates for night time wardrobe assisting were not to be ignored by the girl 
Context: "The rates for night time wardrobe assisting were not something to be ignored by a girl with neither influential contacts"
Hypothesis: The rates for night time wardrobe assisting were not to be sneezed at by a girl with neither influential contacts.
Based on the context, is the hypothesis true, false, or unknown?