To the OP; How well do you know this girl? How did you find her, and what experience does she have in this field? Is she familiar with your pricing structure, and will she be able to hold her own with a potential customer who tries to haggle? Finally is she really aware of what is expected of her for the wage/commission you are offering her?
I have never used a canvasser, neither would I as I prefer to do this myself, but if I were to, I would want to know that the questions asked above would all be satisfied by both parties before proceeding, and supported by a written contract.
John