Eff. stacks = 1000
Hero is BB with AJss. UTG straddles, 5 players call, including Villain in SB. Hero raises to 100. All fold to V, who calls.

Flop: Jh6s5d. Pot = 260. V checks, Hero bets 75, V calls.

Turn: Th. Pot = 410. V checks, Hero bets 175, V raises 475. Hero?

JTs is obvious, but it isn't clear what else he beats me with here. He certainly puts in a raise with JJ in position, and it's hard to see someone l/c OOP with 55, 66. TT is similarly unlikely - would expect him to put in a PF raise 90% of the time.

Relevant history: Last week I played a hand with V that is similar and relevant.
V is older guy who does not seem especially aggressive or a creative player, but may be sticky PF. In past week, a player bet 20, another called, and V overcalled on CO; I squeezed to 125 in BB. All folded to V, who called with QTcc. He then called my flop bet, turned a flush, and called down my triple barrel on a paired board with a river K. I didn't show.

Note that while he was in position in our last hand, his range now still likely includes S/Cs.

Given description, it's hard to imagine that you are good here. However, this is the main reason I hate small bets -- we now have to decide if they are playing back at our small bets or if they have us crushed.

Edit: Granted, turn bet isn't that small, which makes the check/raise a bit scarier. I really don't like committing here w/ one pair and basically no redraws. Calling seems so weak. If he will check all missed rivers, I guess it's OK, but I don't like it.

Given the opponent descript, specifically "does not seem especially aggressive or a creative player", I'd let it go. He has 3 of the sets and all of the 2pr scs.

Flop - I'd go a bit larger.

Turn - I'd mix in a check at some frequency.

After his flop call, I'm trying to get to a cheap river here on this turn. Check turn.

AP: probably this is a "solver call" from the midpoint of our range. I cannot find it though so I prefer a Baluga Theorem "population fold" here.

It’s a call in solverland (probably the best one-pair hand to call with too, given our blockers), but a fold in the real world.