Basically mean Okay. I get it. STFU.
Also, used as "whatever" at teachers or boring conversations.
Example: Math teacher: Anyone got it?
Kid: Sure, sure. *Got back to desk, Listens to iPod, forgetting the work*
Girlfriend: ZOMG! Did you just saw him with her? I cannot believe his with her already just right after our broke up! Blablablblablblaaa
Me: Sure, sure.
Girlfriend: Are. You. Even. Listening.
Me: ...
The state of being more than simply "for sure." Invented in Calgary, the saying is used as a reply to a question when someone is certain about something; when they are 100% positive about it.
The response you give when you don't 100% want to say "Yes" but also don't want to say "No". "Sure" is the answer you use when on the fence about something, but is not an acceptable response to Y/N questions.