And may the blackest curse of God strike me if I'm lying.

5 seconds sound clip from the Anna Christie (1930) movie soundboard.

You can hear this line at 01:26:15 in the DVD version of the movie.

Quote context

[...]

- I wouldn't have the nerve, honest, Matt, if it was a lie. But it's the truth, and I ain't scared to swear it.

- Give it to me. What do you want me to swear? You say it.

- Swear I'm the only man in the world ever you felt love for.

- I swear it. I swear it by God.

- And may the blackest curse of God strike you if you're lying.

- And may the blackest curse of God strike me if I'm lying.

- Oh, glory be to God, I'm after believing you now.

- Now what's the matter?

- Is it Catholic you are?

- No, why?

- Oh, God pity me. Sure, it's some devil's treachery in it. You swearing on a Catholic cross, and you one of the others.

- Well, don't you believe me, Matt?

[...]