Who said "I've trained myself to feel nothing, but that's not living."?

This quote is attributed to Black Widow (MCU).

I've trained myself to feel nothing, but that's not living. - Black Widow (MCU)

"I've trained myself to feel nothing, but that's not living."

Black Widow (MCU) Life

"I've been red in my ledger for a long time. I'm trying to wipe it out."

"Sometimes you need to go back in order to move forward."

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

"You really think you can hold onto the cube? It has a lot of voltage."

"Life is meant to be lived with passion."

"Life is what happens when you're busy making other plans."

"Life is a journey, not a destination."

"Life's too short for regrets."