Ironman 2 Trailers

It is a marvel charecter "black widow", originally a good guy or a bad guy?

At the end of Avengers movie cartoon that is the good side, but after seeing the second trailer ironman looks like she could be a villain, I was not sure that this is because I was thinking.

bad guy. She was originally a Russian spy and assassin, however SHIELD found out about her and offered to work with SHIELD SHIELD I found the black widow because she was trying break (or maybe she's security system) its.

‘Iron Man 2′ Trailer