4 flush board w trips. River play?
 

I got into a debate with my friend about this situation.
Villian is an unknown, Hero just sat down at the table.
Stacks irrelevant. Hero is in SB with JQs. VIllian is UTG.
2-4 5 handed.

Villian raises to 8, Button calls, I call, BB folds.

Flop is AQ2, A and 2 of diamonds. BB check, Hero bets 15, Villian calls, Button folds.

TUrn: Q diamonds. hero bets 40, Villian calls.

River: K diamonds. My friend argues that because an A is most likely for Villian and that he doesnt have the A of diamonds, I should bet to try to get a call from VIllian, takeaway the play of VIllian to bluff me off river if I have no intention to call a large river bet, which I do not.

By betting, he says I might get him to fold low diamonds or even medium diamonds. By checking, I might get bluffed off a hand.

I argue that this this is very player dependent, if he is passive, there is no use betting since he won't bet hands that dont beat me.

What do you guys think?

River:

Re: 4 flush board w trips. River play?
 

Would he check the flop with an Ace? I lean toward check/folding.