Tia/Calypso's divine intervention??....( possible spoilers)
Bootstrap touches Jack's hand in the very beginning, giving him the "black mark". Then when Jack meets Davy Jones, Jones touches his hand and takes the mark OFF. This should mean he's not being hunted by the Kraken anymore, right? But then why does it suddenly come back when he and Elizabeth almost kiss?
ANSWER:
Tia's/Calypso's intervention..It was to stop Jack messing his chances up with Liz IMO..Jack would have lost her if he kissed her there...the ring he took from her hut is made to be MASSIVELY OBVIOUS on that hand just before the black spot appears on it..
This "puling away" is what ALSO causes Liz to become afraid of Jack and the fact that he is suddenly "proving" to care more about her feelings than his own selfish desires. This is a PG 13/Disney movie we have to settle for sexual implications when it comes to the characters and sex talk.
Just before this teaser kiss the two were obviously talking about SEX not marriage...Well Liz was..I'm not so sure about jack..I think it was a bit of both when he said it..Liz is "disgusted" because she thinks he's just talking about sex... Jack suddenly shows Liz that he has more of an interest in having her as a parter instead of just a mere object...Liz is puzzled..and you can see the suspicion in her face.and then she says."why doesn't your compass work?" in other words "its not just sex?"..Jack looks shocked, cornered and he unconvincingly tries to prove that "my compass works fine" He then looks downwards at a cannon that is suggestively placed near Liz...then he tries to escape the awkward situation..Liz is NOT convinced...and this scene was a test, she wanted to see if Jack was actually more interested in her as an object or if he was actually caring about her and what she wants..If he kisses her..he's SELFISHLY kissing her when shes saying its not what she "stands for"..Liz already has feelings for Jack its more than obvious..but she seems to feel safe because she thinks Jack is only ever interested in her for sex..and she feels safe in believing that it could never develop into anything more between them...She's trying with all her MIGHT to make him kiss her..but BAM he pulls away! and she looks quite uneasy with it..as in "WHAT THE HELL JACK SPARROW CARES FOR ME?"
That uneasiness in her face is a warning sign as to what is going to happen later if Jack PROVES to her that he loves her..and its not good place its pointing to..its a place of FEAR...
What I find interesting is that WHEN Jack has proven to Liz that he cares for her by leaving and then COMING BACK for her(what she fears)..Liz DOES FREAK OUT because she realizes that this man loves her. She has her own feelings for him and they have now just totally moved up a level because the man cares for her..he wants to protect her..he puts her before himself..She is in NO WAY ready to accept Jack yet..she chains him up to remove the temptation of him..she forces herself to be with Will even though its not what her heart REALLY wants..Just as she chains him up....LOOK at what is made to be obvious..its the RING FROM TIA'S HUT!..meaning that THIS whole ending happened because SHE had intervened earlier by making the black spot appear..she caused this whole "FEAR of loving Jack" that Liz has..Also the fact that the kiss was stopped gave Jack time to realize that he DOES LOVE HER...So it made sure that ending happened the way it does..and it ALSO gives WILL a chance to see it...!!!
This ending had to happen if Liz and Jack were to realize their feelings for each other.....it HAD to be a life or death moment...in which he realized WHAT was more important to him his own well being/possessions or Elizabeth..He realizes its her..In turn Liz would have never realized her feelings for him had she he NOT come back for her during a life or death moment...Also Jack dies knowing that Liz wants him...and BADLY..the very act of removing him from her life because he is such a "tempting threat" to her makes him smile..the fact she goes into kiss him again but pulls away makes him smile even more and confirm with pride "pirate"..
Tia must have been planning this for a LONG time because the means to bring Jack back from the dead were there in her hut before he even got there to see her.
the most important thing to note is that Jack WAS ready to love her..but Liz Wasn't..just yet...Will saw the kiss..which gives him reason to leave her/do something stupid to himself if she chooses Jack over him..Tia did all this for a purpose..and I think its to make Will the next Davy Jones.