What is the promise of a 100 payment to be received one year from today?

The promise of a $100 payment to be received one year from today represents the future value of that amount. Its present value is less than $100 due to factors like inflation and the opportunity cost of not investing that money today. To determine the present value, one would typically discount the future payment using an appropriate interest rate. Thus, the promise is essentially a commitment to pay that can be evaluated based on its present worth.