You have a decent hand and have bet 2/3 pot on flop, and 2/3 pot on turn. Villain is on button and has called your flop and turn bet. You have a strong feeling he was chasing the flush. River completes any flush draw.

Do you bet on river and if so how much do you bet in relation to pot size?
(Assume still relatively deepstacked compared to the pot)
(Assume you have no reads on this player)

Example:
UTG limps, you limp in MP with 7c7h, button limps, sb completes, bb checks
flop: 2d 7d Js

sb checks, bb checks, UTG checks, you bet 2/3 pot, button calls, sb folds, bb folds, UTG folds.

turn: 4c
you bet 2/3 pot, button calls

river: Qd
your play here???

If you check, what is your plan in response to a bet
If you bet, what is your plan in response to a minraise, standard raise, push?