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1.
A phrase used to make fun of a person for saying something completely obvious.
Person 1: *drops her purse and already leans to pick it up*
Person 2: you dropped your purse.
Person 1: Are you sure?
by Kayla Pape October 15, 2003
 
2.
are you sure means basically are you sure your rght or are you mad/crazy. also can use are you dizzy?
"Why you pullin a shank!"

"are you sure? im not carrying mine!"
by Dees Blud July 17, 2008