Legal analysis: 1. It is a reflection of the true wishes of the parties. The content of the guarantee letter should be the expression of the true intention of the party concerned and cannot be coerced, threatened, induced, deceived, etc.
2. There is no violation of relevant legal provisions; the content of the guarantee must comply with the provisions of the law and cannot violate the prohibitive provisions of laws or administrative regulations, otherwise the guarantee may be invalid.
3. No infringement of the interests of others. The guarantor can only dispose of things that he has the right to dispose of, and cannot infringe on the legitimate interests of others. Of course, in practice, a letter of guarantee is valid and will be protected by the law only if it expresses the true will of the parties and does not violate relevant legal provisions or infringe on the interests of others.
Legal basis: "The People's Republic of China and the Civil Code"
Article 681 The guarantee contract is to ensure the realization of the creditor's rights. The guarantor and the creditor agree that when the debtor A contract in which the guarantor performs the debt or assumes liability when due debts are not performed or circumstances agreed upon by the parties occur.
Article 682 A guarantee contract is a subsidiary contract to the principal creditor’s rights and debts contract. If the principal creditor's rights and debts contract is invalid, the guarantee contract shall be invalid, except as otherwise provided by law.
After the guarantee contract is confirmed to be invalid, if the debtor, guarantor and creditor are at fault, they shall each bear corresponding civil liability according to their faults.