Please, Taran! No! You can't.
6 seconds sound clip from the The Black Cauldron movie soundboard.
You can hear this line at 01:04:21 in the Blu-ray version of the movie.
Quote context
[...]
- Eilonwy, you and Fflewddur go with Gurgi.
- But Taran, that's impossible! Why, you'd be... Taran!
- Please, Taran! No! You can't.
- Wait, Master. Gurgi not let you jump into cauldron!
- Whoa!
- Please, Master! Not go into evil cauldron.
[...]