One little box sells authentic Juicy Couture and other brands like Coach. I've bought from her with no problems. She also sells on ebay under the same name.
In the future you can ask authentication questions on the threads dedicated to this. Every forum has their own.
Also one can do a search of this entire purse forum for sellers like onelittlebox and see what other buyers have to say about them. I have found this very helpful, even more helpful than asking in the mentioned threads.