Dynamics: I've been at the table a few orbits & have a neutral image. Table has been very passive so far - lots of limping with very little raising.
Opponent: unknown straddles UTG to $6. Middle aged guy. Haven't seen him play many hands.
Effective stacks: $325
Preflop: I limp in EP with A♦ 3♦. (I didn’t realize there was a straddle otherwise I may just have folded). 3 others call & we are 5 handed.
Flop: 6♦ 4♦ 6♣. Checked to me & I bet $15. Only the straddle calls. Pot is now $55.
Turn: 7♦. He checks. I bet $25 & he makes it $50. I decide to call. Wasn't sure what to do here. He could be full but he could also be overplaying a worse made hand like trips, a straight or a smaller flush.
Pot is now $155.
River: Q♥. He checks. I knew I had to bet here but wasn't sure about sizing. I wanted to make sure his worse hands call but was also knew I may have to fold if he makes a large check raise. His stack is about $260. I decided to bet $50. What sizing would you use here? Also what do you do if he leads the river for a reasonable amount? I don't think I'm ever folding but wondering if a raise would be an overplay?
Looking for thoughts on turn & river play. Thank you.