sniffing out the bluff

Sometimes, you can just tell your opponent didn't get there. This hand was fun; comments in CAPS; track OUR HERO.
This was the second hand dealt in a $55 buy-in single table tournament, blinds 20/40.
OUR HERO went on to take 1st.

Seat 4 is the button
Total number of players : 10

Seat 2: OUR HERO (2000)

ageah posts small blind (20)
msd21 posts big blind (40)
** Dealing down cards **
Dealt to OUR HERO [ Kh, Js ]
OUR HERO raises (120) to 120 -- EVERYONE FOLDS TO ME; I'LL MAKE A SMALL RAISE IN LATE POSITION; LET'S GET THE PARTY STARTED!
msd21 calls (80) ONLY THE BIG BLIND WANTS TO PLAY...
** Dealing Flop ** : [ 6s, Jd, 3d ]
msd21 bets (150)
OUR HERO calls (150) INTERESTING; I HIT TOP PAIR, NICE KICKER WITH MY AGGRESSIVE PRE-FLOP RAISE; LET'S SEE WHAT THE TURN BRINGS, AS THOSE DIAMONDS ARE SCARY.
** Dealing Turn ** : [ 6c ]
msd21 bets (250)
OUR HERO calls (250) SHOULD I RAISE OR LET HIM BLUFF THE RIVER?
** Dealing River ** : [ As ]
msd21 bets (600)
OUR HERO calls (600) IF HE'S BLUFFING, I WIN; IF HE ACTUALLY CAUGHT A HAND, I LOSE THE MINIMUM
** Summary **
Main Pot: 2260
Board: [ 6s Jd 3d 6c As ]

OUR HERO balance 3140, bet 1120, collected 2260, net +1140 [ Kh Js ]
[ two pairs, jacks and sixes -- As,Js,Jd,6s,6c ]
msd21 balance 880, lost 1120 [ Td Qd ] [ a pair of sixes -- As,Qd,Jd,6s,6c ] MISSED THE FLUSH AND TRIED TO BUY IT ON THE RIVER. DIDN'T WORK THIS TIME!