I play scared

Villain is a loose passive fish. Normally I would put a bet out on this river but I've seen him call down hands like 2 pair in similar situations.

Party Poker No-Limit Hold'em, $ BB (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

MP ($2.73)
Hero ($28.12)
Button ($31.07)
SB ($13.90)
BB ($19.35)
UTG ($22.25)

Preflop: Hero is CO with Ahttp://www.flopturnriver.com/phpBB2/...iles/spade.gif, Ahttp://www.flopturnriver.com/phpBB2/...iles/heart.gif. SB posts a blind of $0.10.
UTG calls $0.25, 1 fold, Hero raises to $1, 3 folds, UTG calls $0.75.

Flop: ($2.35) 9http://www.flopturnriver.com/phpBB2/...iles/spade.gif, Jhttp://www.flopturnriver.com/phpBB2/...iles/heart.gif, 7http://www.flopturnriver.com/phpBB2/...es/diamond.gif (2 players)
UTG checks, Hero bets $1.5, UTG raises to $3, Hero calls $1.50.

Turn: ($8.35) Khttp://www.flopturnriver.com/phpBB2/...iles/spade.gif (2 players)
UTG checks, Hero bets $4, UTG calls $4.

River: ($16.35) 5http://www.flopturnriver.com/phpBB2/...es/diamond.gif (2 players)
UTG checks, Hero checks.

Final Pot: $16.35