Is there an affordable and safe neighborhood in Rio de Janiero?

No, not one.

Please give more info, like your budget. Affordable is a relative term. I assume you think Leblon or Ipanema is too expensive. Also, are you Brazilian or a tourist and are you looking for a long term place to live or just a few month rental? If LT is your thing, you should visit some real estate agents. If ST is your thing, you could try a hostel, get familiar with the area and then look for an apartment in that area. Also, look for roommates, it will cut your costs dramatically.

This may sound strange, but if you are aware of your surroundings and not flashy/flaunting expensive clothing or jewelery, Rio overall is a safe city.

Even weirder, I would say that if you know what you are doing, the favella is the safest place - no really, you might think that this is a crazy statement, but it is true. I don't recommend this at all, unless you are well traveled, can speak Portuguese fluently and have some friends that already live there. But it is dirt cheap and as long as you don't stick out to the banditos, it is really safe in its own way.

I'd say Flamengo. It's in the perfect place. I've been there many times. Send me an email at cadagobr1 at gmail.com if you have any questions.

http://en.wikipedia.org/wiki/Flamengo

try santa tereza...charmy..well situated and quite afordable.
Have a good trip

Santos, much better or even guaruja

No, not even the expensive ones are safe.

I doubt....
Ci vediamo!