Are you here to convert me?
I have a suggestion. If somebody accuses you of trying to win converts or asks you if you are trying to convert them, don't say anything like, "I'm not trying to convert you. I can't convert anybody. Only the Holy Spirit can convert you (or only you can choose to convert)." I've talked to a lot of Jehovah's Witnesses and Mormons, and every time I ask them what their intentions are, why they come to my house, and what they're trying to accomplish, and whether they are trying to convert me, they all give me a variation of that response. The reason I suggest not giving that response is because it comes across as disingenuous. I always strive to be straight forward and honest with people, and I expect the same from them. Mormons and Jehovah's Witnesses are not going door to door for nothing. Their hope--their goal--is that you convert. And they think them being there to talk to you will have something to do with your conversion. Otherwise, there'd be no reason for them to witness to you. And when you witness to others or use apologetics, the purpose is to cause them to change their minds and convert. Just be honest about it. It doesn't mean you have to change your theology. Of course the Holy Spirit has to change a person's heart, but if we ambassadors were irrelevant to the process, Jesus never would've sent us out. It is not impious to say that the reason you are sharing your faith with somebody or offering arguments for your faith is in the hope that they will convert. And if that is your hope, then you are trying to convert them. Just be honest about it. I would have a lot more respect for Mormons and Jehovah's Witnesses if they were just honest with me about their intentions.