"All of that is related to that move away from the kind of hyper-sexualisation of this character and, I mean, you look back at Iron Man 2 and while it was really fun and had a lot of great moments in it, the character is so sexualised, you know? Really talked about like she's a piece of something, like a possession or a thing or whatever — like a piece of a**, really.
"And Tony even refers to her as something like that at one point ... [he says] 'I want some'. Yeah and at one point calls her a piece of meat and maybe at that time that actually felt like a compliment. You know what I mean?"
Scarlett thinks that 11 years ago she would have accepted a comment like that as a compliment as a young woman, but now she wouldn't as she understands her "self-worth".
The BAFTA-winning star is pleased that the world is evolving and now men and woman know that derogatory sexual comments are no longer acceptable.
Continuing her discussion about Tony's line in the Iron Man 2 script with Collider.com, she said: "Because my thinking was different. Maybe I even would have, you know, my own self-worth was probably measured against that type of comment or, like a lot of young women, you come into your own and you understand your own self-worth. It's changing now.
"Now people, young girls, are getting a much more positive message, but it's been incredible to be a part of that shift and be able to come out the other side and be a part of that old story, but also progress. Evolve. I think it's pretty cool."
Black Widow - which is released in cinemas on July 9 - is set prior to Scarlett's character being killed off in Avengers: Endgame but the Jojo Rabbit actress insists that her alter ego's fate did not alter her mindset during the project.
Scarlett said: "This movie became more of a reality, I guess, when we were shooting Avengers: Infinity War, so I did know about the character's fate."