Late comment is late but no it doesn't. Desu is just there to make it more polite, considering it is said. At the end of nearly every sentence when speaking Japanese. If it actually meant something then you wouldn't be able to us it anywhere.
Well. I had actually forgotten something. You're half right. Desu means is,am or are. It doesn't mean any specific thing and can be used in anyway. If you asked Kawaii Desu ka. You would be asking if it's cute. It's being short for it is so you would be asking "is it cute?" And the 'is' would be the Desu and the Ka being the question mark.
This Is How It Would Go: 2P Germany: Need Some Help? *Smiles* Me: Id Say So, As It Seems Like I'm In A Trunk....*Grabs Hand* 2P Germany: *Dusts Off My Pants* You Ok? Me:*Glops Him* OH Me Gotie! You Are Sooo Cute!! 2P Germany:*Blushes* Get Off Me..... Me: *Gasps* Hes Blushing!!*Faint From Fangirl Overload* 2P Germany:The Fuck!