Well, you've got it.
3 seconds sound clip from the McLintock! (1963) movie soundboard.
You can hear this line at 01:59:09 in the Blu-ray version of the movie.
Quote context
[...]
- Been some mighty sneaky goings-on here during that raid.
- Who was it said only a trollop would kiss a man before they were formally engaged?
- Oh, but we are engaged, sir.
- You are?
- That is, with your permission.
- I guess this is the only engagement, that ever started off of a spanking.
- Mm-hmm, I reckon Birnbaum was right.
[...]