A dressed woman is a woman who has clothes on. A dressing woman sounds like a woman who is in the process of putting her clothes on. A 'dressing woman' might refer to someone whose job it is to dress someone else. I've never heard this phrase before, but it makes sense. Royals and the aristocracy would have 'ladies in waiting', and performers in the theatre have 'dressers'. 'Dressing woman' could be a mistranslation of one of these terms.