Regardless the words, I finally reduced my understanding to a rather simple structure. Both that which is faith and that which is belief come from the same wellspring. It is consonance of heart-mind. Belief is of the senses and the constructs of mind. Faith is of the heart , sometimes with mind, sometimes in spite of mind…
I won’t try to convince you that faith is the virtue central to the five virtues but I will say that when considering the exact nature of Li, which is not simply ‘rites’ it is a deep harmony with Heaven, thus appearing to be ritualistic or ‘proper’, one must consider the trinity also bringing faith into a whole new light.
Well, if we are defining xin as harmonizing with Heaven and Earth in the symbiotic relationship that you describe, then I would agree that it would be the central virtue.
I disagree with your philology on xin, that is all.
For free access to my earlier posts on voluntary simplicity, compulsive spending, debting, compulsive overeating and clutter write: vfr44@aol.com. Any opinion expressed here is that of my own and is not the opinion, recommendation or belief of any group or organization.