My advice
Honestly? My advice is to simply await the complaint, and if a single
letter of what you allegedly said is out of order, you threaten the complaining employee and your company with legal retribution. It's at least one part histrionics, though.
Someone once complained that I had a "Satanic" wallpaper on my computer desktop. When HR asked about it, I played this strategy. I looked them straight in the eye and said, "Satanic? Who said?" They were, of course, unwilling to tell me. "Bring me a written complaint," I said. "And if it says
Satanic I'll sue everybody who touches it."
The wallpaper, incidentally, was a seven-pointed star from the work of Aleister Crowley. Not quite Satanic.
I got called in to answer for a drug scandal at my work. It was a painful coincidence--my dealer was named as a dealer, but it was wild speculation by an angry man going down for sexual harassment. See--my dealer at the time only handled pot, mushrooms, and acid. As soon as the word "cocaine" entered the discussion I simply got very "sensitive". But I joked that if the company was concerned about cocaine, they would have to fire half their adjusters. I think HR was painfully aware of this. Furthermore, I asked them directly who accused these people, and in less-than-subtle terms, capitalizing on the word "cocaine", said that I wished to sit in a meeting with HR and this person so that I could personally explain the nature of slander, what it means to a company, and what it means to a person. Just as a note on how thin you cut it: I also resented the idea that they were dealing "out of the garage". When it came to work, it was usually delivered directly to my desk. I didn't tell HR this last part, of course. I just asked HR if the complaining employee knew how dangerous it was to be so slanderous. I actually made it into a "stoner persecution" issue, and got away with it.
Point being, if the complaint comes down, don't sweat it. If there's even a comma out of place, take it as a personal affront and let HR know in no uncertain terms that the complaint is false. Basically make it clear without saying that if they choose to discipline you they will be taken to court and it will be ugly. (I got away with that a couple of times; it's effective, but only if you don't really mention a lawsuit. I mentioned that this would cause "a mess" for everyone, and hinted after "reputation"; they understood.)
If the complaint is harassment, you'll have no problems. At no point were you harassing her, and you might be able to lodge a complaint against her with your HR. I
never tolerated "anonymous" accusations, and I found I could usually get my company to drop whatever they were wondering about if I stood firm but polite on that road. If she cannot show that you were "harassing" her, you can file a complaint for her needless harassment of you.
It's a sticky political game, a conscientious two-step of sorts. But you just bare your teeth and remember that you're enjoying this more than your actual job. Well, it helps if you actually do enjoy the political fight. But I lose those so rarely that I might be overconfident. (It's been literally 10 years since I lost a vital argument with an employer.)
Factors to consider: location, time, and the nature of the original conversation itself. People stopped coming to our smoking circle for such reasons; a bunch of non-Christian, reasonably educated people smoking and thinking and talking. Nobody wanted to level harassment complaints about the things we talked about because nobody wanted that sanctuary violated like that. So location is key. Also, if your conversational associate will back you, it should be very easy to establish that you were having a legitimate conversation, and if somebody wants to eavesdrop on your complaints, they shouldn't have a problem. Drop a joke in there somewhere about the Patriot Act. "At least it's harassment and not something like
terrorism. Then you could send me up the river
legally for this kind of nothingness."
Make the issue the paranoia of the complaining employee, and put your sympathies with HR for having to deal with this: "I'm sorry you guys had to get involved; if I'd known I shouldn't ever have a conversation, I wouldn't have said it." If done subtly, this kind of thing is tremendously effective. You're on the company's side, see? You
like HR and don't want them wasting their time for such petty issues. You're stunned that it's gone this far and want to help make it right, but you've got to be kidding me that I can't have a
conversation .... People are going to eavesdrop, but they shouldn't be getting upset when they're not invited to the conversation they're intentionally listening to. Depending on your HR, and their disposition, you might even get away with: "Well I feel funny using the men's room now. What will she complain if I shake it off that I'm committing sex acts in the bathroom?"
Bring out the insanity, put it in front of them, and
do not let an eavesdropper set the tone of the process to come. Wait for the complaint, don't worry about it. Just put the
whole situation in context for the company (not the religious part, just the dynamics of what happened) and then play it like a used car salesman.
If you've ever seen Bob Tilton's various ministries, adopt that kind of faux sincerity. His schmooze is an amazing one.
luck and an evil grin to ye,
Tiassa