Which document verifies a borrower's rights to the property in a mortgage agreement?

The deed is the correct document that verifies a borrower's rights to the property in a mortgage agreement. It is a legal document that transfers ownership of the property from the seller to the buyer. In the context of a mortgage, the deed demonstrates that the borrower is the legal owner of the property and has the right to encumber it with a mortgage. Essentially, the deed provides proof of ownership and establishes the borrower's rights to the property in question.

While the other options play significant roles in the mortgage process, they do not serve as verification of ownership. The loan application is a document that outlines the borrower's financial situation and requests a loan, but it does not confirm rights to the property. The mortgage commitment letter indicates that a lender is willing to issue a loan to the borrower based on provided information, but it also does not confirm the borrower's ownership of the property. Lastly, the title insurance policy protects against loss from title defects, but it does not serve to establish rights over the property; rather, it ensures that the title is clear at the time of closing. Therefore, the deed stands out as the definitive proof of the borrower's rights in the context of a mortgage agreement.