Legal analysis: Letters of guarantee and letters of commitment are valid if they are voluntarily signed. To be legally effective, three conditions must be met: 1. The letter of guarantee and the letter of commitment are the true expression of one party’s intentions; 2. The letter of guarantee and the letter of commitment are valid The content does not violate the relevant provisions of laws and regulations; 3. The content of the letter of guarantee and commitment does not violate the principles of public order and good customs.

Legal basis: Article 685 of the "People's Republic of China and Civil Code" A guarantee contract may be a separately concluded written contract, or it may be a guarantee clause in a principal creditor's rights and debt contract. If a third party unilaterally provides a guarantee to the creditor in writing and the creditor accepts it without raising any objection, the guarantee contract is established.