Winamax -Holdem - 8 players
Hand converted by PokerTracker 4

MP+1: 22.92 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: -, Hands: 16)
Hero (CO): 70.07 BB
BTN: 24.92 BB (VPIP: 42.86, PFR: 7.14, 3Bet Preflop: 0.00, Hands: 14)
SB: 21.46 BB (VPIP: 50.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 16)
BB: 23.79 BB (VPIP: 50.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 16)
UTG: 42.38 BB (VPIP: 56.25, PFR: 6.25, 3Bet Preflop: 0.00, Hands: 16)
UTG+1: 46.56 BB (VPIP: 33.33, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 9)
MP: 22.92 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 16)

8 players post ante of 0.08 BB, SB posts SB 0.5 BB, BB posts BB 1 BB

Pre Flop: (pot: 2.17 BB) Hero has K K

UTG calls 1 BB, fold, fold, fold, Hero raises to 4 BB, BTN calls 4 BB, fold, fold, UTG calls 3 BB

Flop: (14.17 BB, 3 players) A J 5
UTG checks, Hero ?

Here is a situation that I face a lot. Flopping a second pair, while it's quite likely that one of the preflop callers have an Ace in their hand. Should I Cbet here? If I do and get called, I will be scared of an Ace and probably leave the hand there. If I don't bet tho I will be giving a free card to diamond flush draws out there.
Thanks for the help

easy check. a fd isnt a huge concern to begin with but the Kd in your hand makes it a lot less likely that someone does have an fd anyway. you can call pretty much any turn depending on action/sizes etc.

Check/call if btn bets. Bet turn if checked through on pretty much any card (this would be a value bet imo).