How very nice. You've come to fight the dragon who's been such a bother to us all?
6 seconds sound clip from The New Adventures of Winnie the Pooh - A Knight to Remember (S3E39).
You can hear this line at 00:12:34.406 in the Blu-ray version of the TV Series.
Quote context
[...]
- Come on, knight. I got to get you to His Royal Poohness, the king of all Chessland.
- King Pooh. That's who. Hoo hoo hoo!
- Greetings, Your Royal Royaltiness.
- No, Your Most Lowly Highness.
- I bring you good news. I bring you one dragon slayer to go.
- How very nice. You've come to fight the dragon who's been such a bother to us all?
- Well, uh, no, actually, I was just passing through, and...
(Eeyore braying, earth rumbling)
- Oh, my. Will you look at the time? I really must be going.
- If I'm not back soon, start the dragon fight without me.
- Eh, can't go slaying dragons dressed like that. Nope. No, sir. Just won't do.
[...]