Conflating Hitchcock and Disney has made my day!
Most folks probably know the line best from Doris Day's rendition, penned by Jay Livingston and Ray Evans, where it has been changed from the Italian/Latin "Che sera, sera" to the Spanish (and collaterally, French) "Que sera, sera."
Livingston cribbed the "che sera, sera" line from the movie The Barefoot Contessa and changed it into Spanish because of that language's global popularity.
(Then, separately, there is Jimmy Fontana's song "Che sará," popularized by José Feliciano.)
Livingston/Evans source: <http://www.quesera-sera.com/fullspeed.htm>.
See also: I learned language in the American educational system, and all those Latinate languages have too many weird accents and they're all just a dialect of the same dead language anyway.