1. Written in block letters, signed by the parties, indicating the date and place, preferably with handprints and witnesses.

2. The agreed affairs do not violate national laws and regulations or public order and good customs.

3. The agreed affairs shall not harm the rights and interests of the third party.

Specific commitments, dates and signatures, etc. And the meaning should be true. The promisor shall be a person with full capacity for civil conduct, with legal contents and no violation of public order and good customs.

This is in black and white. This is written in black and white. This metaphor is very accurate. The written evidence that has been chiseled out cannot be denied or repented. From: Yuan: The second discount of "Seeing Money Slaves Buy Enemy Creditors" by Anonymous: "Don't talk nonsense, it is written in black and white. If anyone breaks his word, he will be fined 1000 yuan and used by those who don't break their word. Synonyms are: conclusive evidence, antonyms are: there is no evidence, black and white are commendatory words, which can be used as predicate, attribute and complement; Describe a written certificate.