Who said "I won't let you down."?

This quote is attributed to Iron Man (The Avengers).

I won't let you down. - Iron Man (The Avengers)

"I won't let you down."

Iron Man (The Avengers)

"I am Iron Man."

"Genius, billionaire, playboy, philanthropist."

"If you're nothing without the suit, then you shouldn't have it."

"I've successfully privatized world peace."