Unraised pot preflop.
3 handed, meaning me and two suckers.

I had :Kh: :Jh: OOP

Flop was


I checked flop (it was checked through), turn came another heart, I checked again (weaker flush would bet, right?) some guy bets half of the small pot, 2nd villain folds, I smooth call.

River I donkbet pot it. He folds. Was I destined to rake in nothing or did I misplay my hand?