Can you sell technology without patent? Is the transaction guaranteed?

It can be sold, but there is no guarantee.

But it's better to apply for a patent first to protect your rights and prevent the other party from going back on their word.

Before you apply for a patent, you can't get transfer protection without the certificates of the applicant and relevant personnel.

Patent protection refers to the purpose that an inventor achieves protection by applying for a patent right for his invention and creation.

The purpose of applying for a patent in time is to gain the initiative in the market competition, prevent competitors from applying for a patent for the same invention, and thus ensure the safety and reliability of their own product production and sales.