Hi jgnat, First off, sorry about the typo of sewing vs. sowing.... geesh, I would have gotten a weird mental image too.
I agree about avoiding an "in depth" discussion of the "Trinity", because that is a mystery that we Christians still grapple with. She has however mentioned to me that it is "not in the bible" so JW's don't believe it. Since this was one of the first doctrinal points she mentioned to me, I tried to give her a simple explanation of why the word "trinity" does not appear in the bible and where the concept came from.
Essentially, this is what I shared with her. It is an attempt to describe the nature of God when confronted with some very interesting, and seemingly contradictory scriptures about who is the Father, Jesus the Son and the Holy Spirit. Rather than cherry pick one or a few scriptures that might portray them in one particular light, the church fathers in the fourth century tried to find a harmony of the scriptures by describing the one true God as having three distinct characters. They acknowledged then this was a feeble attempt to describe God's character by human words and understanding and that it was a "great mystery" of the faith. It still is today.
I shared with her the concept of the trinity that an old saint in my church once told me. He told me that we know from the bible that God is Love. Not just that He loves us, but that he is inherently Love. He didn't need to create us in order to have Love. He wasn't missing Love with a need to be fulfilled through our creation. No, before time as we know it, He WAS Love. How can this be? Who did he love? Did He love himself? Yes, in that mysterious way, He did love himself because we believe that the Father, Son and Holy Spirit co-existed in perfect harmony and love before the world began.
It is a very difficult concept to grasp and some people and religions, rather than struggling with the mystery and accepting that perhaps the human mind is not expansive enough to truly know the nature/ character of God, choose to focus only on those scriptures that make God more like us and therefore more understandable.
Lastly, in another feeble attempt which anthropomorphizes God. I tried to apply the concept to myself. If I were to truly love you and make you my wife, I would undoubtedly have three very unique "kinds" of love existing in me and acting upon you. They would be: Agape (Godly/Spiritual) love; Philos (brotherly/friendship) love; and Eros (erotic/passionate) love. At different times you would see the different loves manifested. At times, if you didn't know better, you would think by my actions that only one kind of love was in play. For instance, when having passionate sex with you as my wife, you might think I was all about Eros. But yet, you know that the Agape and Philos are still there inextricably intertwined in the one Stuart that Loves you. Yeah, I know, it certainly is a flawed analogy, but nothing can truly describe the mystery of the Trinity either.
You never know. Perhaps this might help someone else understand or at least appreciate the concept us Trinitarians grapple with.