Is it possible to love someone that you don't know? I think so. I have felt love for people I have never met, and people that I have just met. But I think that is different from the "perfect love" that Mormon writes about. I think that in order to love God perfectly, we need to know Him. And as we come to know Him and Love Him then we begin to place our trust completely in Him. With our trust in Him we need not fear, because we know that He loves us perfectly and will work all things together for our good.