Difference between Co-Signing and Guaranteeing a Loan:
Both co-signers and guarantors are responsible for the loan if the borrower does not pay the loan.
Co-signing the loan means you and the other borrower are both borrowing the loan so the lender can ask payment from you instead of asking the other borrower.
Guaranteeing the loan means that if the borrower cannot pay back the loan, the lender can then ask for the guarantor to pay for it.