… be the unit of account in which prices of goods and services are denominated to anchor our sense of the relative value of different goods and services. … and finally, hold a stable predictable value, or purchasing power, over time. This is essentially what we mean by price stability. Underlying these attributes of money is trust.
You accept money as payment only when trusting that others will do so as well, now and in future. You hold money trusting that it will maintain its purchasing power over time. Without trust, money does not function. So, where does trust come from?