The correct spelling of the phrase "wast naive" is actually "was naive." The reason for this discrepancy in spelling lies in the old English language, where "was" was spelled as "wast." However, this spelling has since been updated to its current form. "Naive," on the other hand, is spelled phonetically as /naɪˈiːv/, with the long "i" sound and emphasis on the second syllable. So, the correct way to spell this phrase is "was naive."