A guarantor is a person or company that guarantees that a loan or other type of debt will be paid. Usually, this person or company agrees to pay another person's debt or perform that person's duty if he or she should fail to do so himself or herself. The term is most commonly used in reference to financial assistance.A parent who cosigns a student loan for a child could be considered a guarantor; if the child defaults on his or her debt, the parent would be held liable for the remainder of the loan.ost 54. Co-signing and being a guarantor are two different things. Every co-signer is a guarantor, but not every guarantor is a co-signer. If you pledge to repay a debt of another without the possibility of personal return, then you are the co-signer.