Your girlfriend may feel that the womens black dress shoes that you bought for her are way too tight and she won’t be able to put them on. Just so you may not feel bad ideally she has let you know that she really loves them and would like to get even more but you by accident ordered her the wrong size.
To avoid having to return womens black dress shoes in your girlfriend try hinting around to see what size shoe she wears and then you won’t have issues. If you find that to be unsuccessful simply because she might think of it has being suspicious, then consult one of her friends that is aware her best and get her what shoe size she wears.