Who said "Death is the one mission you don't come back from."?

This quote is attributed to Black Widow / Natasha Romanoff.

Death is the one mission you don't come back from. - Black Widow / Natasha Romanoff

"Death is the one mission you don't come back from."

Black Widow / Natasha Romanoff Death

"I used to have nothing. Then I got this job, this team. It's all I have."

"Compromise where you can. Where you can't, don't."

"I'm always picking up after you boys."

"The world doesn't change without sacrifice."

"Death doesn't scare me anymore."

"Death and I are old friends."

"Welcome to my world."

"Death is just the beginning."