“Quite simply, you can’t have a testimony until you bear it to someone. At the moment that you tell someone that you know X is true – even if you don’t know it yet – the Spirit will testify to you that it is indeed true. It may sound a little iffy, but I can tell you that it’s true. I had the same issue as you did at one point. I wasn’t sure that the Church was true, but I wanted a testimony. I got up in testimony meeting (the same time that I described earlier, in fact) and told everyone that I ‘believed’ the Church was true. I prefaced it by telling everyone that I didn’t know for sure yet, but I had heard that this was the way to find out for sure, so I was going to give it a shot. Sure enough, it worked. The Spirit told me that the Church was indeed true. In fact, the Spirit is telling me again that the Church is true as I’m writing this response. It’s really cool. I suggest that you try it for yourself. If you want to know for sure that the Church is true, tell someone else." (“The Board,” 9/14/2005)
I’d suggest they would do better by being “Bereans” and actually read the Bible to see if what the LDS teaches is true. If they did that, they would leave the cult of Mormonism.