That premise is undermined later in the film, when Eve's elaborate attempt at seduction is futile.

Nope. Great line, but no. He has no concept of sex.

Exactly. He said the word "escort" a little oddly, because the word was unfamiliar. The way he spoke made it come across as having a double meaning, but Chance wasn't aware of that. The movie is full of little misunderstandings of that kind.
But Chance wouldn't have assumed anything about sex, because he didn't understand or have any interest in sex. That's made very clear during Eve's attempted seduction.
"You can't handle the post-truth!"

I did not think CG thought that escort meant have sex. I don't think he knew what sex was.

In the context of this scene "escort" = "accompany". Nothing more to it than that.

this is my favorite line in the film , when eves husband ask Chauncey to escort his wife to the Russian ambassador reception , i think its safe to assume that CG does not understand the meaning of the word " escort " and assumed it meant blank his wife
It is safe to assume that Chauncey didn't know what "escort" means, but it isn't safe to assume that he thought it mean having sex, since he's presented as an asexual permanent child with absolutely no concept of anything in the world other than gardening.

If that is what he thought it meant, then why didn't escort her when she threw herself at him in the bedroom?
Democracy is the pathetic belief in the collective wisdom of individual ignorance. H.L. Mencken