Sure or not sure

I am not sure he understands what is "sure" - I mean what sure means but he gets the drift.
In this act he is playing with his toys and it is close to his bedtime.

"Ashir"
"Yes Mommy"
"We are ready to go to bed, clean up.."
"OK in five midets" (minutes)
...after 5 minutes.....
"Now we are done, Ashir, do you want to go pee?"
"No" (Standard answer for anything that takes him away from his toys)
"Are you sure?"
"Hmmm if I am sure?"
"Then you may not pee"
"If I am not sure?"
"Then you will have to go to the bathroom"
"Then I am sure"