Most Helpful Guy
It's not about what she wears. It's her looks that matter more than anything. What she has on will have no effect on whether we approach her or not.
The main (and arguably only) reason why we're scared of approaching a girl, is that we think she is too attractive. Our brain processes this in such a way that we believe her looks make her better than us (because for us, looks play a significant part). We'll also believe that she is aware of this, thus we'll think she'll think she's better than us, and not want to have anything to do with us. Which is why we don't bother approaching her if she is too good-looking.
As you can see, it doesn't matter what she's wearing.