(This is a grunch from a green fish.)

You don't have a made hand, but you've got a gutshot straight flush draw.

Jd gives you a royal straight flush (one out).

Any of the other three jacks gives you a nut straight (three more outs).

Any non-jack diamond gives you the nut flush (eight more outs).

And that not counting any aces, as a pair of aces will win you the hand if the villain has KX or QX, but not if he has KK or QQ.

So that's 12 outs that will give you the adsolute nuts, with 46 cards you haven't seen, making your drawing odds 3.73:1.

Pot odds are 3.16 BB. If you bet and he check-raises, then you're behind the odds curve. He hasn't check-raised so far, but that doesn't mean he won't.

Check. If you don't get one of your outs on the river then hope he checks again and you can get to a showdown for free. Fold if he bets.