Answer:
Cognitive Dissonance Theory
Explanation:
At first, Sarah strongly believed it's wrong to steal, but after stealing a nail polish her mind set about stealing changed, this can be explained as Cognitive Dissonance
In the field of psychology, cognitive dissonance can be defined as the psychological state when a person holds two or more contradictory beliefs, ideas, values, or participates in an action that goes against one of these.
Dissonance is an unavoidable consequence of making a decision. Cognitive Dissonance Theory suggests that when a person's beliefs and desires conflict, they will experience discomfort as they become aware of the inconsistency.