Was just playing some free poker and i don't get why i lost On the board there was a 9♣K⋄3♣4♠K♠. My opponent had Q⋄9♠. I had 9♥3♠ i have a pair with the 9's and the 3's but my opponent only had a pair of 9's Any help would be awesome :)
The king on the river gave your opponent two pair, kings and nines. It also changed your best hand, giving you two pair, kings and nines. Your opponent had a queen kicker, which plays on this board and is the sole difference between your hand and your opponent's. In hold-em, the best hand is determined by the best 5-card combination of cards for each player at showdown.
Your opponent's best 5-card hand here: K♠K⋄9♣9♠Q⋄
Your best 5-card hand: K♠K⋄9♣9♥4♠
Had the board not paired on the river (and as long as the river is not a queen), you would have won this hand with your two pair versus your opponent's one pair of nines.