The “na na” makes all the difference — turning a fact into a feeling.
The phrase "Shinseki no ko to o tomari dakara de na na" roughly translates to: shinseki no ko to o tomari dakara de na na
It looks like you’re quoting or referencing a phrase from the Japanese light novel and anime series Shin Sekai Yori (新世界より, From the New World ), specifically the opening line of the folk song “Yuki no Hōkai” (雪の崩壊, “The Collapse of the Snow”): The “na na” makes all the difference —