Questioning another’s understandings is how we can establish a dialogue, to share ourselves, as we come to know and love another more fully. It happens more face to face, rather than through detached interactions such as we find here, where as you say, we are likely to come to justify our beliefs.
I agree that, in search of the truth, we must question ourselves as to how we “know” what we “know”.
A journey that constitutes a lifetime cannot be summarized to fit into this format. Suffice to say that the outcome is a fundamental truth, which lies at the heart of my understandings - the reality of my personal existence, and its relationship with Existence itself, to which words can only point.
We can describe the nature of Existence as being relational, triune. As an image of our Source, we exist as persons-in-the-world, a connectedness of a particular kind of individual being, with what is other to it. Relationality is manifest throughout creation, where we find different forms of being expressing the particular ways in which they interact and combine in the formation of ontologically greater systems, which then demonstrate novel kinds of relatedness. As persons, regardless of our genetic make up, psychological as well as physical characterisics, and whatever blessings have been bestowed upon us, we are as individual expressions of mankind, now broken, and ultimately one in the communion of self and other that occurs when we give of ourselves, when we love, in other words. There is nothing more real, nothing of greater and lasting value. In these moments, we connect with that Perfect Relationality that is divine and eternal, from which all creation springs, here and now, as it was when, for the purposes of this thread, the first of every individual entity came to be as an expression of what they are. Creation is true, here and now and everywhere and at every time, each form of being in its moment.