It all depends on what he bet. You are 9 outs to the flush plus, if he holds the K, you are 3 outs to the top pair. 12 outs comes to about 2:1 pot odds needed to call. So unless he goes all in and takes away your odds, its usually a good call.

According to Harrington, 14 outs gives you an even money bet if you are sure to see both the turn and river. I like your bet here.