No, no, Helen. It's not true.
4 seconds sound clip from the The Seven Year Itch (1952) movie soundboard.
You can hear this line at 01:32:40 in the Blu-ray version of the movie.
Quote context
[...]
- Now, who could've tipped her off? Kruhulik, that's who!
- There's a woman in this apartment. I just know there is.
- No, no, Helen. It's not true.
- Don't lie to me, Richard. Don't lie to me.
- Who told you? How did you know?
- I'm going to shoot you dead.
- Helen, I can explain everything: the cinnamon toast, the shower, everything.
[...]