Allow me to translate as I Speak 50,000 words of English including thousands of 4 syllable words. In the interest of linguistic fluidity I find myself referencing the Urban Dictionary more often than I reference my two other languages.
Finna is ebonics for “going to”, and in this case probably the alternative derivation of “gonna”.
https://www.urbandictionary.com/define.php?term=finna
God help this country.