In olden days when a boy used to get attracted towards a girl or prosposed her .  The best setence to get rid of that boy used to be, ' You are jst like my brother. To be safe can I tie a Rakhi on your wrist.'

 In the modern days when a guy is attarcted towards a girl or proposes her.  The reply is much cuter although very dangerous. 'You are just a good friend of mine. I have no such feelings for you.'
they still want a window of opprtunity to be left opened. :-D