[BluffTHIS!]

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In a limped pot you may be able to get away from it.
Since you raised preflop I would reraise. Your opponent is likely putting you on aaxx. The villian could have an open str8, flush draw, two pair, bottom set or even aaxx himself.
I reraise and gladly pay off jjj

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This is correct unless you are dealing with a total rock who always checks top set to the preflop raiser. With this big of a drawing board a good player as well as a bad one is going to try to push someone off of AA by a checkraise with a draw. Merely calling rather than reraising is also an option to see if a draw completes on the turn and gauge villain's reaction to it before committing the other half of your stack.