Difference: guarantor v. surety

A guarantor promises to pay the debt if the debtor cannot pay. A surety is a guarantor that promises to pay when the debtor does not pay. A surety is an insurer of the debt, whereas a guarantor is an insurer of the solvency of the debtor. A suretyship is an undertaking that the debt shall be paid; a guaranty, an undertaking that the debtor shall pay. Stated differently, a surety promises to pay the principal's debt if the principal will not pay, while a guarantor agrees that the creditor, after proceeding against the principal, may proceed against the guarantor if the principal is unable to pay. A surety binds himself to perform if the principal does not, without regard to his ability to do so. A guarantor, on the other hand, does not contract that the principal will pay, but simply that he is able to do so. In other words, a surety undertakes directly for the payment and is so responsible at once if the principal debtor makes default, while a guarantor contracts to pay if, by the use of due diligence, the debt cannot be made out of the principal debtor. (CCC Insurance v. Kawasaki, G.R. No. 156162, June 22, 2015)