The door is cold, and newcomers need to be sincere.

My understanding is that the surface is cold and the heart is deep. If you want to touch my heart (pursue me), you need to show sincerity.

The "door" is deep and cold: the door, the portal, is what it looks like on the surface; Courtyard, courtyard,

Intrinsic refers to the heart. Using intricate techniques (let's just say … I can't remember clearly), the correct word order is "the door is cold and the court is deep", and it is easy to understand that "newcomers need sincerity". "Newcomers", people who come over and are close to themselves need "sincerity", sincerity, sincerity.