Villain is kinda tricky, possibly even half-decent for the stakes, 21-17 and 3.5% 3-bet over 200 hands. He doesn't fold flops to c-bets much (33%) and is kinda floaty/likes to steal pots.
He's possibly steaming from a hand in the last few minutes on another table against me where I stack him JJ vs AK blind vs blind.

Obviously I'm not concerned that my flush is only the second nut.
River I bet to try and rep a block/fear and hope that he'll shove over vs my obvious weakness with his entire range.

Party Poker No-Limit Hold'em, $0.50 BB (5 handed) - Party-Poker Converter Tool from FlopTurnRiver.com

BB ($53.55)
UTG ($41.33)
Hero (SB) ($50)
Button ($86.97)
MP ($53.45)

Preflop: Hero is SB with Q, 10
3 folds, Hero bets $1.75, BB calls $1.50

Flop: ($4) 6, 4, K (2 players)
Hero bets $3, BB calls $3

Turn: ($10) J (2 players)
Hero bets $8.50, BB calls $8.50

River: ($27) 2 (2 players)
Hero bets $8,