Probability semibluffing situation

[Stormwolf]

Lets say you have KhTd and the flop is Th6h2s, your opponent checks you bet he calls, now a Qc comes on the turn, now he check-raises you. You believe he is semibluffing with a heart draw. The fact you hold the Kh makes it less likely he holds suited cards on hearts, doest any one how much its that decrease?

[AaronBrown]

You have to be careful with computing probabilities of what your opponent holds. The probability of the next card off the deck can be computed with precision, but what your opponent holds depends on what hands he might have folded or otherwise played differently.

What I can say is if you see three hearts out of six cards, the odds that two drawn at random are both hearts is (10/46)*(9/45) = 4.35%. If you didn't hold a heart it would be two hearts out of six cards, (11/46)*(10/45) = 5.31%.