I use the analogy of love’s existence as an argument about God’s existence. The common refrain of non-believers is that since we cannot prove God exists, he does not.
I ask if there is anything that exists that one cannot prove (with evidence acceptable the person). I sometimes ask what proof would be sufficient for them of the existence of God.
I then ask, “Does love exist?” Few would say no. “How do you prove love exists?” The kinds of proof they suggest are almost exactly the same kinds of proof of the existence of God...
I would say that while I may believe it, I do not KNOW it.