OOP with flush 100nl

Main UTG vil is 18/13 and haven't seen anything out of the ordinary. Seems a below avg player with stationy tendancies and predictable postflop play. Riv card is almost the Nut worst card which should mean...EZ c/f rite?

$0.50/$1 No Limit Holdem
6 Players
Hand Conversion Powered by weaktight.com

Stacks:
UTG Smali ($110.30)
UTG+1 undeadchen ($233.55)
CO Sam Rodstin ($166.50)
BTN PhxSunsfan1 ($100)
SB BJLTNYK ($100)
BB Hero ($137.20)

Pre-Flop: ($1.50, 6 players) Hero is BB
Smali raises to $4, undeadchen calls $4, 1 fold, PhxSunsfan1 calls $4, 1 fold, Hero calls $3

Flop: ($16.50, 4 players)
Hero checks, Smali bets $12, 2 folds, Hero calls $12

Turn: ($40.50, 2 players)
Hero bets $31, Smali calls $31

River: ($102.50, 2 players)
hero.?

I'd bet smallish because you're never bluffing here so no need to polarise your range and worse hands aren't raising

Yeah, this player is not imaginative enough to raise with worse, so I make it $31 again & fold to a raise.