When Wendy met Rachel in the washroom, a lot of thoughts are playing inside her head. Why is she here? So that vermin knows her? And she is acting nice and polite with her?
Wendy does not need to ask an expert to know what ideas are running inside that snake's head. Rachel obviously knows her because of her fashion house in their city. The Fairy Factory has a lot of branches abroad and their designs are always received by the people with praises and open arms. Their limited edition designs, especially their jewelry sets, are always sold out and people are getting eager to see their next releases.