Oh, Your Grace, I'm dreadfully sorry. It shan't happen again.
7 seconds sound clip from the Cinderella (1950) movie soundboard.
You can hear this line at 01:11:08 in the Blu-ray version of the movie.
Quote context
[...]
- Bruno. Yes, Bruno! Quick, get Bruno. Get Bruno!
- Oh! Of all the stupid little idiots. I'll do it myself. Get away from me.
- I'll make it fit. There. It fits.
- It fits?
- No!
- Oh, Your Grace, I'm dreadfully sorry. It shan't happen again.
- Come on, come on. Get up, Gus-Gus, get up.
[...]