Villain seems very loose preflop but I don't have much history with him.
I think I could lead for $12-14 on the river and fold to a shove.... but since I checked, what do I beat here and could he be turning his hand into a bluff?

Converter is a bit messed because this is on Cake... I have 100BB and villain has me covered.

$0.25/$0.5 No Limit Holdem
5 players
Converted at

Stacks:
CO ($103.60)
BTN ($9.80)
SB ($42.95)
BB ($50.85)

Pre-flop: ($0.75, 5 players) Hero is [Ac]
Hero raises to $1.75, I(o)I(o)I calls $1.75, 1 fold, BTN calls $1.75, 2 folds

Flop: [2d][Kh] ($6, 2 players)
Hero bets $4, I(o)I(o)I calls $4, 1 fold

Turn: ($10, 1 players)
Hero bets $10, I(o)I(o)I calls $10

River: ($20, 1 players)
Hero checks, I(o)I(o)I bets $34