2nd pair plus + flush draw

[NNH]

10NL – Practicing multi-tabling, so no reads at all.
Effective stacks are $10. I open .40 from UTG+1 with AdJd, Villain calls from CO. All fold.

Flop KxJx6d
I bet 3/4 pot, he calls.

Turn is a non board pairing diamond
I check he bets about $2 into the $2.70 pot.

What’s the best line on the turn? As played, what’s my plan.