Hero, Natasha Romanoff from Avengers (2012)

Clint Barton: [Natasha has freed him from his restraints] Tasha, how many agents did I-?
Natasha Romanoff: Don't. Don't do that to yourself, Clint. This is Loki. This is monsters and magic and nothing we were ever trained for.
Clint Barton: Loki, he got away?
Natasha Romanoff: Yeah. Don't suppose you know where?
Clint Barton: [Shakes head] Didn't need to know. Didn't ask. He's gonna make his play soon though. Today.
Natasha Romanoff: We gotta stop him.
Clint Barton: Yeah, who's "we"?
Natasha Romanoff: [Shrugs] I don't know. Whoever's left.
Clint Barton: Well, I... if I put an arrow through Loki's eye socket, I'd sleep better, I s'pose.
Natasha Romanoff: Now you sound like you.
Clint Barton: But you don't. You're a spy, not a soldier. Now you want to wade into a war. Why? What did Loki do to you?
Natasha Romanoff: He didn't, I just...
[pauses]
Clint Barton: Natasha.
Natasha Romanoff: I've been compromised. I got red in my ledger. I'd like to wipe it out.

- Natasha Romanoff from Avengers (2012)