The alternate line for the passage in question is invisible in the online version of the database because somebody enclosed it in angle brackets. Here 'tis:

Well, how <do you expect me to know who in Hell you> are?

Rise Up Singing renders it:

Now how the heck am I to know just who you are?

which may well also be inaccurate. "Sweet san fairy ann" is what I hear in the Kingston Trio recording, but what it means has been a puzzle to me for 30 years.
-Joe Offer-