A fixed-rate mortgage locks in one interest rate for the life of the loan, while an adjustable-rate mortgage's rate can change periodically based on market conditions — a fixed-rate loan can still be refinanced like any other loan, and an adjustable-rate loan absolutely still charges interest, just at a rate that can move.

A mortgage is a two-party security instrument between borrower and lender, while a deed of trust adds a third party — a trustee — who holds legal title as security until the loan is repaid. Which one is used doesn't determine the interest rate, and a deed of trust is commonly used for home purchases in many states.

The promissory note is the borrower's personal, signed promise to repay the loan under its stated terms; the deed is what transfers title, not the note. It's not a promise about future refinancing, and it isn't a government guarantee (that's a separate feature of certain loan programs).

LTV compares the loan amount to the property's appraised value (loan divided by value), which lenders use to gauge risk — it isn't an income-to-payment ratio (that's closer to a debt-to-income calculation), isn't a total-interest figure, and isn't a comparable-sales analysis.