I was never more serious in my life.
4 seconds sound clip from the The Milky Way (1936) movie soundboard.
You can hear this line at 01:08:13 in the DVD version of the movie.
Quote context
[...]
- But this is just like committing suicide.
- You don't know me? Oh, now, you're being facetious, aren't you?
- I was never more serious in my life.
- The boy I knew went away and never came back.
- Yes, he did. I'm the same fellow. I can prove it. I'll show you my driver's license.
- I met a boy once that... Well, to say the least, I liked him very much.
[...]