550bb deep with nut flush on paired board

[snowbank]

It's against the same villain in this hand: http://forumserver.twoplustwo.com/showth...=0#Post12708179

history: I have position on villain, and have really been pushing him around all session. I've been 3 betting him a lot, and postflop bullying him pretty hard. He's been pretty passive for the most part.

Full Tilt Poker, $2/$4 NL Hold'em Cash Game, 6 Players
LegoPoker Hand History Converter

BB: $1,027.20
UTG: $467.50
MP: $2,357.80
Hero (CO): $2,202
BTN: $231.75
SB: $826.40

Pre-Flop: K[img]/images/graemlins/club.gif[/img] Q[img]/images/graemlins/club.gif[/img] dealt to Hero (CO)
UTG folds, <font color="red">MP raises to $14</font>, <font color="red">Hero raises to $48</font>, 3 folds, MP calls $34

Flop: ($102) 7[img]/images/graemlins/club.gif[/img] J[img]/images/graemlins/heart.gif[/img] 4[img]/images/graemlins/club.gif[/img] (2 Players)
MP checks, <font color="red">Hero bets $65</font>, MP calls $65

Turn: ($232) A[img]/images/graemlins/diamond.gif[/img] (2 Players)
MP checks, <font color="red">Hero bets $144</font>, MP calls $144

River: ($520) A[img]/images/graemlins/club.gif[/img] (2 Players)
<font color="red">MP bets $300</font>, Hero ????

I think I'm good here, but he plays super passive, and this is the first time he's fired out the river. Also, I think he may be a bit fishy, and if I raise here I think there's a chance he could raise with a worse hand thinking he's good. So I'd really hate to raise and fold to a worse hand.