Preflop
I would just fold. SB is the worst seat on the table, and you dont have a premium hand. 3-betting QJs OOP is a little to fancy for 2NL. People are going to call way more, than you like, and then you are OOP with a mediocre hand in a bloated pot. I am not very exited about that.
Flop
You managed to hit a pair, but its important to remember, that your pair is not exactly the nuts. He is a fish, so he can absolutely have a 5 in his hand, and since he is so passive preflop, he can also have AQ or KQ. Maybe even KK or AA from time to time. So you have a marginal made hand, and for that reason I prefer to check and hope, that he check back. At least your bet was small, which I like.
Turn
Still kind of the same story, and again I am happy, that you at least bet on the small side. You need to keep his range wide for this bet to be for value, and even though fish notoriously dont fold, you dont have to completely overplay your hand.
River
Not a great card obviously. I am not so worried, that it helped him, because did he really call twice with just A high? Maybe AX of hearts exactly, but other than that probably not. It will however be scary to hands like QT and 99-JJ, so totally onboard with checking here. And when he bomb the river I think, you need to give him credit and fold.
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