OK This happened yesterday at a $200 NL cash table. Very deepstacked for me both myself and opponent had $500+ (250bbs).
I know opponent well, we play tgether every day. He is a fairly solid and winning player.
However, he sometimes will call potsized bet on draws. He can also call as a slowplay. He is not the sort of player to call a bet on this flop with a hand like an overpair - he would raise or fold.
If he calls on draw and misses he is capable of bluffing river for sure.
He can be a tricky player, check raise as bluff etc.
I am on BB with 56off
6 way pot
Flop was:

(Pot = $12)
SB checks
I bet pot
button calls
Turn was

(Pot = $36)
I bet $30
Opponent calls
River

(Pot = $96)
Your play?