here's a little something to clear things up.....
in the original japanese version, naruto ends a lot of his sentences with the expression "dattebayo." It doesn't have any particular translation. it's just supposed to be an annoying way of speaking. so judging by the fan reactions to the ever-so-hated "believe it," the translators did their job well in trying to convey his annoying exclaimations. but even so, "believe it" is still aggravating as FUCK