"Enough to bring joy to the most joyless critics, isn't she?"
"Mmm. And in the hands of a real purveyor of the arts, she could be something in this country. Shame, she's fallen in with you."
"(laugh)You really are better on the page, Mr. Bennett, hard as that is to believe."
The Greatest Showman
What's the grammatical structure of "hard as that is to believe" here?
I guess he's being offensive to the critic because the critic provoked him first. So I understand what this means but I don't understand the grammar of "hard as that is to believe".
Can anyone help me with this?