Final answer:
A person who guarantees repayment of a loan if the original borrower fails to do so is called a guarantor. This role is separate from collateral, which involves pledging an asset.
Step-by-step explanation:
The individual who assists the applicant in obtaining a loan by agreeing to guarantee repayment of the loan in full either by signing the original mortgage or by a separate guarantee agreement, without their income being used to qualify for the loan, is known as a guarantor. This person is legally bound to repay some or all of the money on a loan if the original borrower does not, putting them in the same position as the borrower regarding responsibility for the debt. In contrast to collateral, which is a separate form of security, the guarantor provides a personal assurance to the lender.