$1-2NLHE, HU: Donk river bet induces bluff raise

$1-2 No-Limit Hold’em Heads-Up Cash
$313.70 Pot
Villain: from UK

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In this hand I 3-bet to $20 with Ah8h, get called and see a flop of (J 7 J) two hearts. I C-bet $21.10 and am called. The turn brings an Ace and I could well bet here but opt for pot control and it goes check-check. The river is a blank 4 and I like my hand now. I thought his hand would be quite weak so I opt to donk $21.30 into $82.20 to confuse a little. When he raised to $116 I snapped it off.