I'm certain Rabbit will help find the nobody that took Tigger's voice, even if he doesn't believe in them.
7 seconds sound clip from The New Adventures of Winnie the Pooh - Tigger Got Your Tongue? / A Bird in the Hand (S3E10).
You can hear this line at 00:06:59.333 in the Blu-ray version of the TV Series.
Quote context
[...]
- We'd better get some help finding his voice.
- Aha! Caught you, you tool-snatching varmints.
- Think they're so smart, do they? Hmm! Well, I'll show them.
- That's the last time they'll use the south tunnels.
- Huh. There's a reasonable explanation for everything. Things just don't disappear.
- Tigger, what are you doing with my vegetables?
- No, no, no. Excuses won't do you any good. I saw you.
- I knew there was a reasonable explanation.
- But, Rabbit, Tigger says he was saving your vegebibbles from the nobody.
[...]