when to bet ? help pls newbee question.

hello all.
i m a newuser on this forum and a beginning player, i m needing your help to awnser to some question.

how i can know my opponent has a AA or KK?
when i have a top pair with a good kicker.
how can i know i m not trapped?
my other question is about bets.
exemple i had

my hand is AK'os
i raise preflop.
somebody call me. he is a good player

-> flop is Ad 9c 4d

i raised, he called
turn is Kd
my question starts here.

i think i have to bet this turn to know if he had the flush
-> river is 6s
if he raise he had probably it

i m asking this question because always at this point if he checks the turn, i check , scared about the flush, and always he bet the pot on the river.

sorry for my english, i hope someone have managed to understand [img]/images/graemlins/smile.gif[/img]

thank you.

Clearly bet the turn - with 2pr top pr I would bet 3/4 pot - shows enough strength to force a lay down by anyone without the flush - and if re-raised - fold

If he just calls then you have to bet the river as well - can get expensive but there is no alternative - as you say - if you check the turn and he then bets the river you're on a hiding to nothing

[Skuzzy]

I like checking the turn here. I think a bet only gets called by a hand that likely beats you with the flush possibility being out there. The check encourages a weaker hand or even no hand to bluff at it on the river representing a flush. This lets you call the river pot bet and pick up a decent pot you could easily have lost.
This costs the same as a pot bet on the turn and has the advantage of letting you see the river and a showdown. You would have to fold to any re-reaise on the turn here and probably fold to a much larger pot size river bet into you if you bet on the turn.