According to what I have been told, they do not think you are a Christian unless you are a baptized Jehovah's Witness who believes what they believe.
And they do not believe Jesus is God as the Son of God. But they believe Jesus was created, and if I remember correctly they understand the Bible means Jesus is Michael the Archangel, or something like this. If you are going to talk with them, I think you can let them speak for themselves about this.
When I have talked with Jehovah's Witnesses, I do not assume what each one believes, because there can be ones who are realizing they no longer believe what they have been told by the organization. I have been told ones have trusted in Jesus, but they stay in order to reach others. And ones then might get put out.
So, I do not approach someone who is a Jehovah's Witness in a one-size-fits-all way. But Trinitarians generally consider the Jehovah's Witnesses to be a cult, meaning they are well-organized with false doctrine and practices. Plus, they have their own Bible translation called the New World translation.
I do not assume that they are all alike, like they might try to show they are all in unity. Each one is created by God and unique. So, I invite each one to speak for oneself, about what is that person's actual experience about God and His word and finding out how to love the way Jesus wants.
And I share things of God's word which have blessed me and be kind and gentle and humble. Be a good example.
Trust God to guide you. He will use whatever He has you do, whatever He has you say. And know that His word, whatever He has you sow, will produce His result >
"'So shall My word be that goes forth from My mouth;
. It shall not return to Me void,
. But it shall accomplish what I please,
. And it shall prosper in the thing for which I sent it.'"
. . . . . . . . . . . . . . . . . . . . (Isaiah 55:11)