Functional Order: Ni/Fe/Ti/Se
Auxilliary Function: Ni
Amy loves riddles and mysteries. She always creates riddles and paper chases for her partners birthday or their wedding anniversary and later when she arranges her disappearance. Amy also has a love for more intellectual pursuits like psychology and literature, designing personality tests for a company and telling Nick about her favorite Jane Austen Books at one of their dates. She is sort of arrogant about her academic pursuits and feels she has to bring Nick to her level so that they should speak the same language. When she realizes that her husband won‘t life up to her impossible high standards and has been u faithful, she becomes furious with him and starts an elaborate revenge scheme to bring him done. Her whole existence becomes focused on that one goal and she carefully crafts every step towards her end goal. Her love for Nick becomes obsessive and she is more interested in molding him towards her idealized image of how he should be rather than accepting him as a human of flesh and blood with all his flaws.
Dominant Function: Fe
Amy is a master manipulator. She has only a loose sense of identity and molds her persona in order to best accompany whatever person she is with. She can play the intellectual progidy of amazing Amy for her parents, the mysterious and seductive stranger on her dates, the sweet and unassuming housewife towards her neighbors and the cool girl for her husband Nick. Beneath all of this though Amy is a ruthless psychopath that has no real sense of identity and defines herself solely by her external image and how other view her. She is highly successful woman that has earned many awards and fame in the academic world, but always needs this appraisal to fill the void within. Amy plays along with what the society and those around her expect her to be rather than creating a unique identity of her own. She is great at assessing other people personalities, wishes and intentions and can show them what they want to see. But while she is incredibly attentive towards others feelings, she fails to notice her own emotions. It takes her time to figure out that she actually wants to be with Nick and only tries to punish him, so that he will change for her. Rather than accept him as an individual with all his flaws, she wants him to adapt to the image what she things a perfect husband should be.
Tertiary Function: Ti
Amy is cold and ruthless in the pursuit of her goals. She is calculated and strategic in framing her own murder upon Nick and is able to momentarily detach herself from her feelings to get along with her plan. Her Ti, like all her functions, is quite twisted and causes her to develop a disturbed view on reality: Nick failed to life up to her internal standards she set for him so he must be punished. Nick destroyed her carefully crafted social image and took away her identity by reducing her to a mere housewife, so he murdered her - All of these conclusions might seems gross and delusional on the outside, but to her they make perfect sense. Her Ti helps Amy not only to execute her plan, but also to rationalize her actions. Not only before herself, but also before others, like when she quickly comes up with an excuse for her murder of Desi, inventing a story of having been held captive by him. She even manipulates the evidence to support her claim, fooling an entire police station. Still as her Ti is still on the level of a tertiary function, her lies get seen through by some, like inspector Rhoda, but she still escapes using emotional manipulation, which comes way easier to her (Fe auxiliary).
Inferior Function: Se
While she might be a skilled manipulator and schemer, Amy lacks real world experience. She lived a sheltered life, reading a lot about the world, but rarely leaving her own four walls. She is somewhat naive and helpless when she gets robbed on her flight and gets caught of guard when physically threatened. While she always cared about her looks and appearance when with Nick, her real personality cares way less about such things. Instead she feels a sense of liberation by cutting her long hair and neglecting her physical appearance and taking on a entirely different look/persona. Under stress she is shown to neglect her physical needs (not caring when her full body is covered in blood after she murdered Desi, forgetting to eat or only eating fast food during her escape). She is also reluctant to end her plan with her suicide, showing a hesitation from drastic action. It is only under extreme stress or danger that she makes decisions, like when murdering Desi, seeing it as the only way to get back together with Nick. In these rare cases she is quite capeable of acting on her feet, even though she prefers to carefully plan things out before.