What is trust certification can you tell me what it is not if you have it or explain to me what trust certification is and

If two-factor authentication is enabled on your iPhone, it becomes a "trusted" device once you enable "Find My iPhone." A trusted device is where a verification code is sent. When you try logging into an Apple service that requires you to enter your Apple ID username & password, to verify your identity, you will be asked to provide a verification code. Again, this code would be sent to your trusted device or devices if you have more than one.

Ref:

• Two-factor authentication for Apple ID - Apple Support
• How to add, remove trusted device for Apple ID two-factor authentication - iBulletin
• Get a verification code and sign in with two-factor authentication - Apple Support

What are these 2 devices?

Trust Certificates are what is used to get info transfer between parties encrypted & private.

It's to prevent others getting my private information, only when you have a secure connection will it transfer any info.