Folding AA, top set vs obvious flush

[luckydonut]

PokerStars 2/4 Hold'em (9 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: 2+2 Forums)

Preflop: Hero is MP2 with A[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">UTG+1 raises</font>, <font color="#666666">1 fold</font>, <font color="#CC3333">Hero 3-bets</font>, <font color="#CC3333">MP3 caps</font>, <font color="#666666">4 folds</font>, UTG+1 calls, Hero calls.

Flop: (13.50 SB) 8[img]/images/graemlins/spade.gif[/img], T[img]/images/graemlins/diamond.gif[/img], 9[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(3 players)</font>
UTG+1 checks, <font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP3 raises</font>, UTG+1 folds, <font color="#CC3333">Hero 3-bets</font>, MP3 calls.

Turn: (9.75 BB) A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, MP3 calls.

River: (11.75 BB) 5[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets</font>, <font color="#CC3333">MP3 raises</font>, Hero wants to die.


Are we absolutely 100% certain that villain holds K[img]/images/graemlins/spade.gif[/img] here, probably with another king? Can we sleep soundly after folding? Can we call without the only reason being that you can hit "show cards" in a pathetic kind of way whilst he takes down the pot?

Does anyone really raise without the nuts here?

Well a player who had read my hand perfectly might have a crack at the pot with two red queens or kings, but have you ever seen that happen at $2/$4?

I folded, proud of my discipline at first, but it's really eating me now... Am I actually ahead 1 time in 14?