AKO vs a good player

[PokerBob]

canterbury 15/30 9 handed
villain here is a regular in this game. he knows and respects my play and i know and respect his.

I raise in EP with AKo, folds to villain who 3-bets, folds back to me and i make it 4, villain just calls.

flop HU: 642r
I bet, he calls

Turn: K
I bet, he calls.

River: 4

I think about betting and think about checking. What do i do and why?