"Would you be so kind as to find the literature that contains the apology over 1914?"
That's a great idea. Make her feel like you could reconsider your position if you were to learn the organization humbly apologized. Put the burden of research on her and let her go.
If she really does take your salvation seriously she is going to have to do an awful lot of reading through that old Rutherford crap, ending in failure to find an apology. It's a win/win.
Just might be the ticket to awakening yet another mind.