Most Helpful Guy
It should be a two way understanding, without being nasty. You should understand that she might not be interested and she should understand that you might be hurt. Both of you can remain respectful and then part company if you so choose. It doesn't need to be a huge deal.
Most Helpful Girl
Umm... no one want's you to sit and smile... common decency is just fine.
But come one, being rejected really isn't the reason to get all pissy. Of course, as a woman, I shouldn't be commenting on that because I've never been rejected and all that.