There is a problem for that statement if taken at face value for it says that even the demons believe, and tremble even as they do so.
Demons aren’t people, they don’t have access to saving grace. They made their choice long ago and are stuck with it. However even the vilest human can receive forgiveness and eternal life just by asking for it (and really meaning it, of course). Osama bin Laden can be saved if he wants it, but Satan and his demons can’t.