This is one I have been thinking about a lot, not sure if my line was good here so wondering what you guys might have done different.

I have just 33 hands on villain here, but he has a decently wide range and is playing at 39/12 when this hand happened. He hasn't shown a great deal of capability to bet too much postflop, AF is 1.

We've seen him call 3 bets preflop with A4s already but we can't remember / don't have time to look up the postflop action on this hand and why he took it to showdown.

As played, I'm basically happy to jam it in on the flop but don't get action. I still think I'm ahead on the turn but much less so than previous streets. My thinking is that since we are both so deepstacked (220 BB+), I'll check/call all the way down, barring a hideous river card, so I can commit to showing down what I think is a winner but not have to throw in a couple of buyins to do so.

As it happened, I did end up having to get everything in anyway. He has a wide range we know, but he's not the most aggressive player on the planet from what we've seen so far. Are we getting this in every time? Are there different lines we can take? Could we justify a bet/fold on either turn or river?

First off, that's a great flop for us. Given your description of villain he absolutely can have 6's in his range but he's also likely to have a lot more as well and we certainly expect to be ahead. Bet for value is good.

I'm not a huge fan of the check/call line on the turn versus this villain type. I think when he checks behind we're either losing value or letting him draw for free and when he bets big like this we're left in a tough spot. All options open to us after his large bet seem kinda horrible. Folding seems really weak especially given that our hand is now under-repped. Raising effectively means shoving. We could be drawing to 2 or 3 outs if called. Calling then just prolongs the pain since we're quite likely (and do) face another big bet on the river.
Villain appears to be passive (over a very small sample) so is it likely he plays a flush or straight draw like this? Probably not. That takes away a lot of the hands we're ahead of that might do this. Same goes for him turning some king of underpair into a bluff. Your one-pair hand is probably beat so a disciplined fold is probably best.

Thanks, this all makes really good sense. I think a bet/fold on both turn and river might make more sense in this spot, since he calls down with worse and is only really raising with better. I think my issue of late is I'm not taking opponents' postflop aggression stats seriously enough, and this is a great example of that.

He showed KJ to out-twopair me by the way.