Well, first off, I wouldn't refer to their faith as "The Truth". Whenever one does that, it makes them think that you might still believe it is the absolute only way.
This has not happened to me in a very long time with someone that I actually knew from the borg.As I recall, the last time it did, I was quite nervous inside and I had many mixed emotions. I think I just told them that I appreciated their concern, but I was just fine.
Now days, I believe things would be entirely different in such a conversation. There is no lingering doubt, guilt or low self respect. I think I would handle it just as I did to the last witness that came to my door. I would tell them that I appreciated the efforts of taking their personal time to call on me at my home. Then I would tell them that at one time I was deep into that particular belief system, but had long ago decided that it was not for me. I smile and I am most friendly, but I do not invite them in and I do not take any literature. When they leave, they realize that they have conversed with an x-jw who was once even a full time Pioneer; one who now has got her wits about her, is at peace and quite happy. I believe that alone would make them think a bit.
/<