it won`t hurt a bit...
the terrible lie associating with means of immense pain and agonizing, torturous procedures that doctors, surgeons, nurses, dentists, etc. tell you just to shut you up before they do something you`ll never forgive them for.
ie. "Now, this won`t hurt a bit..."
"LIAR!!"
'It won`t hurt a bit...' my ass.
"LIAR!!"
'It won`t hurt a bit...' my ass.