What is Believe It!?
1.
The most horrid, terifying term in the history of anime dubs.
Derrived from
In short: "Dattebayo" is a cool way to end a sentance. "Believe it" is not.
"I'm Naruto uzumaki, and I'm gonna become the best Hokage ever, believe it!"
VS.
"I WILL be Hokage, just you wait! Dattebayo!"
See
2.
English Naruto dub's awesome and splendid translation of Naruto's catchphrase (dattebayo in Japanese). Many hardcore anime people complain that it is stupid and unfaithful to the original, but do not realize that leaving Japanese terms in an English dub is foolish and defeats the purpose of dubbing.
DUB-"Did I say believe it!? Well, BE-LIEVE IT!"
NON-DUB-"Did I say dattebayo? Well, DATTE-BAYO"
See