Dattebayo with its two variations Dattebane and Dattebasa, you may have heard in the anime series Naruto and now in Boruto. These three variations are catchphrases or verbal tics used by the Uzumaki characters.
They use these catchphrases at the end of their sentences, especially when they get excited or overwhelmed.
Naruto inherited it from Kushina and down the line, Boruto got it from Naruto. Kushina hoped for Naruto to not inherit the verbal habit.
Naruto seemed excited when he found out his mother too used such a catchphrase.
The catchphrase is a childish and abrupt way of speech used by Naruto, Kushina, and Boruto.
Sounds right enough considering their excited, loud, and vibrant personality the catchphrase just sounds perfect when they say it.
Breakdown of Dattebayo
Dattebayo is not a proper Japanese word. But let’s break it down because the individual components actually have meaning in the Japanese language.
“-tteba” is used mostly at the end of a sentence to emphasize a speaker’s intent.
“–tteba” can imply the meaning, “I told you” or “I am telling you” or something along the line. It is a way of affirming what the speaker has said.
“-tteba” is further broken down into “-tte” which means, “said” and “ba” used for emphasis.
“Da–” is an informal version of the standard “desu” used at the end of many Japanese sentences. “Da” itself is not a verbal tic but a common way of ending a sentence used in real life. Hence, adding “-tteba” seems common as well.
Naruto adds “-yo” for emphasis. While Kushina’s speech, replaces it with “-ne” and for Boruto it is “-sa”. The “-yo” is added to “-tteba” in a standard Japanese sentence to end it with emphasis.
All three parts are commonly added to finish a Japanese sentence to signify the speaker’s confidence or exasperation.
“Believe it!”

Translation of the word in the series is “Believe it!” or “You Know!”
Whenever they would get excited or would want to convince someone they end up using their own version of Dattebayo.
This is the only explanation that I can find. I tried to bring to you any available explanation especially that of Masashi Kishimoto but I was not able to find any.
Also, read In What Episode does Naruto Meet his Mom? Naruto Meets Kushina Uzumaki!
Should you use it??

If you plan to add it into your own vocabulary you are free to do so. But, the only issue is that “Dattebayo” is not a commonly used term in the Japanese language.
This is most specifically used by the Uzumaki trio and as a Naruto fan, you can definitely use the word.
As you may have noticed in other anime series “Dattebayo” is never used. The reason is that it is not a part of formal or informal speech patterns.
The parts of the words are perhaps used in standard Japanese sentences but the whole word is only seen in “Naruto” and “Boruto”.
(I do personally like Shino’s Nazenara)
But, as a proud Naruto fan, we should make it part of our vocabulary Dattebayo….
Thanks for reading!!!!!