Just so we can put all that opera in English firmly behind us, here are two (two!) great performances of “scherza infida,” in Italian in the approved manner. The first is Joyce DiDonato, the second Janet Baker.
(Also, did you know that apparently you can get “scherza infida” as a ringtone on your phone? I learned this on the internet just now. I don’t think I’d want my phone to be tinkling “scherza infida” at me every time someone called – but hey, that’s just me.)