Why do I believe as I do? The simplest answer would be lived experience.
As a child I believed in the stories that I was told by adults - I believed that the British Empire was benevolent, that butter rubbed onto a burn would promote healing and that going swimming after eating lunch would lead to drowning. Time, education and experience as I grew up dispelled many of these 'truisms'.
By my late teens, besotted by all things scientific, I decided that the biblical stories I learned in Sunday School and scripture lessons were not to be believed. Instead of God creating all things including humanity, I decided that humankind had invented the idea of deities. Not an unreasonable point of view.
I maintained this line of thought until I was 33 years old. By this time I was a wife, a mother, a teacher and an angry feminist. I was also empty inside, devoid of any ability to cope with the sudden death of my father and the stillbirth of my sister's first baby. Something was missing deep inside me. That something was not belief, it was faith. These two words are very different concepts.
I experienced a conversion experience that was entirely private and very personal. The best explanation I can give is that it was a wake up call and an invitation to change. I was quite shocked and could not shake it off. The first call was followed up by a second one and this time I answered in the affirmative.
The woman of disbelief became a new person, one who was open to seeking new meanings in the scriptures, open to greater love of self and of others, and able to hold doubt in one hand and faith in the other. I was eager to learn more and rather timidly began attending a local church where I found a community where I could participate, learn more about living the christian life and contribute to the activities of the congregation. I began to grow in faith and my inner emptiness was filled with peace instead of anger, with love rather than harsh judgment of others.
I still attend that same congregation and I am proud of the ethos of love, inclusivity and compassion that drives us to be the heart and hands of Christ in this present time. I have never regretted answering the call to embark on a new journey of discovery nearly 50 years ago. I have discovered the "peace that passes all understanding" that comes with faith rather than mere belief.
I'm not sure that I have answered the OP's question but it was a profound one and deserves a profound answer.