Just because you "know" something, it doesn't mean it is true.
Just because you don't know something, it doesn't make it false.
LDS history is riddled with lies: Some told to protect lives. Some told to conceal truths. Some told to escape prosecution. Some told to keep the government from taking property away from the church. Some told to promote faith. But LDS history is riddled with lies.
The historic reality of institutional lying does not render our faith itself a lie. But perpetuating the lies today is increasingly perilous.
You tell the truth. Faith cannot be based on anything other than the truth. Everything else is not faith.