Which document is commonly required by a lender when money is borrowed to purchase real estate?

The correct answer is the promissory note, which is a crucial document in the borrowing process for purchasing real estate. This legal document serves as a written promise from the borrower to repay the loan under specified terms and conditions, including the amount borrowed, the interest rate, the repayment schedule, and the consequences for defaulting on the loan.

The promissory note ensures that the lender has a tangible agreement that outlines the borrower's commitment to repay the borrowed funds, making it a fundamental aspect of real estate transactions. It is a binding document that can be enforced in court if necessary, providing legal protection for the lender.

In the context of the other documents mentioned, while the loan agreement outlines the overall terms and conditions of the loan, it is the promissory note that specifically details the borrower's promise to repay. The deed of trust is related to the collateralization of the loan, creating a security interest in the property being purchased, while the borrower's affidavit may involve declarations related to the borrower’s identity or the status of the property but is not strictly required for the borrowing process itself. Thus, the promissory note stands out as the essential document required by lenders when funds are borrowed for real estate purchases.