In this spot I'm obviously trying to sell the ace. Is my play believable? And even if it is, do we expect it to show a long term profit?
You win a small pot when he can't beat 45s and lose a big one when he can (most of the time) so I don't believe it is a profitable move. As has already been stated he has already put a lot of his stack in so he is committed to the hand now so no point trying to take it off him.
You seem to think his most likely holding here was an ace so it makes even less sense trying to take him off the hand here.
dn