Steve says, "She isn't like this with anyone else," and he's right.
To most of the other Avengers, Natasha has never sounded anything other than sure of herself. There are times when she makes it sounds like she doubts her decisions. Clint and Steve have heard this, because she trusts them, and they know that.
Bruce is different. She can't trust him, of course. No one will ever trust Banner again. But, then again - she can. The spider trusts the elephant, just as deadly and destructive, only in a totally different manner. To Bruce, Natasha allows herself to be self-deprecating.
One of the rules to survive the Red Room was to never show weakness. Wolves surround and tear apart the weak ones. Natasha burned, enough to keep the wolves at bay, always and forever, it's the reason she's still alive. With Banner, she opens herself up and shows the ice in the heart of the flame.
She’s been wanting things she can’t have, recently. She’s been wanting to be human, and for it not to be a pretense. She’s been wanting to walk the streets without knowing every angle a sniper could fire from, enter a room without looking for every scrap of cover in case of a firefight. She’s been wanting to tell someone how she feels. She’s been wanting to feel emotions the way people are supposed to feel them, in your heart, not watching them from behind a glass screen.
Natasha’s been wondering and wanting things that she will never ever be, and wanting what you cannot have leads to misery and madness. Natasha assumes this, the truth is that she’s never been stupid natural enough to want things she won’t get.
There’s supposed to be someone special in your life, isn’t there? There’s supposed to be someone you can tell everything to. Natasha decides to try out Bruce Banner for size.
She tells him how when she’s waiting and watching for something, and she can’t fall asleep, any time she needs to pass the time, she makes an estimate. She counts missions, counts accidents, counts attacks, and she estimates approximately how much damage she’s done. How many people, in her life, she has killed. As many as she can remember. She knows there are more she can’t remember, because they laid her on an operating table and wiped them. They wiped her memories, not clean, but red, with a bloody cloth, they blurred and smudged and stained them with red until she couldn’t see them anymore, only left with the sensation of ribs cracking underneath her foot, and necks breaking in her grip.
Not so surprisingly, but Bruce could relate.
The only difference was that Bruce never remembered. He didn’t have anything to go off, just the wrecked feeling of waking from the hangover to end all hangovers, and a sense of guilt not creeping but flooding in, filling up his torso and arms and legs until his whole body was flushed green with guilt and shame and regret and death, and he was naked and someone was staring at him, and he was sitting in the middle of a huge mess. On a bad day there were bodies lying around him, too.
Natasha understood. Some, not all, but enough. It suddenly seemed like a great idea, talking about her feelings. There was finally someone worse off than her, and she took a perverse pleasure in it. She wondered if she should feel ashamed of that, then decided it was a human, natural thing to be pleased that someone was in trouble like you, but worse. You didn’t feel so bad about what you’d done because – wow, they skipped school for a week, I just hit the teacher with a spitball.
Natasha tries not to think about how Bruce Banner was just a scientist doing research, and he’s still just a scientist, he just got unlucky in a major way. Natasha was twisted into an honest to god monster, from then, till now, she’s had complete control of her actions.
Natasha knows she didn’t ask to be placed in the Red Room, didn’t ask to be thrown to the wolves. It’s not her fault she learned how to fight them.
Steve tells her this, when she decides to take the chance of telling him her feelings. Steve knows better than to say ‘you’re not a monster’, knows how hollow the required words can be. Natasha learns that he knows this after S.H.I.E.L.D falls, and she opens up a crack, just to relieve the mounting pressure of feeling inside her. She tells him how she thought that being on the side of the angels was a matter as simple as joining S.H.I.E.L.D and putting her talents to good use, but it was a bad use, it was always a bad use, it was never for a good purpose and maybe she’s been lying to herself the whole time about wanting to be good.
Steve repeats her words to her (the wrong business, Romanoff) and she smiles a little, because he’s probably right about that.
But it was only a crack she let him see, and when she pours her waking nightmares, her body count, the wolves taking chunks out of her heels, he has to tell her, “Natasha, you know you didn’t choose to be trained like that? You didn’t get a choice,” because she didn’t and she didn’t choose to have her base ability to bear children ripped out of her abdomen at age sixteen, did she, she didn’t choose the Red Room. But I was good at it, she wants to cry, and she knows Steve can’t ever understand this part of her.
Because Natasha Romanoff is good at it, she is the fucking best, and really, she’s a hundred times worse than Banner because she was awake every single second she was sowing chaos and squeezing the last breaths from a nameless body, creating the single, perfect red hole in the suit of a well-known one, and really, Natasha isn’t the kid who hit the teacher with a spitball, she’s the one who murdered the principal.
Can you wipe out that much red?
She’s not sure what she wants from Bruce. Maybe the answer to whether she's been at least honest with herself.