Would there be positive interest rates on bonds within a world along with absolutely no risk (no default risk, maturity risk, and so on)? Why would lender demand and borrower be keen to pay, a positive interest rate within such a no risk world?
Yes, there would be positive rate of interest within risk-free world. It is because regardless of risk, lenders of money must postpone spending during the time the money is loaned. Lenders, then, lose the opportunity to invest their money for that period of time. In order to compensate for the cost of losing investment opportunities while they postpone their spending, lenders demand, and borrowers pay, a crucial rate of return, the real rate of interest.