I'm looking for a casual Strapless Cotton White Dress?
Like this: http://images.wikia.com/kingdomhearts/images/c/c0/Namine.jpg
Yes, I know its not real. Please and thank you 
i like this dress and i think it suits your requirements? http://www.newlook.com/browse/productDetail.jsp?icCategory=cat10019&icProduct=193714210&icSort=-bestSellerScore
i dont think you should wear it will black shoes like in the pic. maybe some killer heels like these ones
http://www.newlook.com/browse/productDetail.jsp?icProduct=191901510&icCategory=cat10013&icSort=-bestSellerScore