Final answer:
Therese's key motivation is exemplified by the phrase which shows her realization that personal freedom and self-assertion are her true driving forces.
Step-by-step explanation:
The phrase that best supports the inference that Therese recognizes Jocint's key motivation comes from the passage where the character's internal conflict and motives are explored. The most telling phrase is "a clear and exalted perception enabled her to dismiss the suggestion as trivial" which shows Therese's realization that her previous concerns were insignificant compared to the newfound liberation and self-assertion she experiences. This moment of clarity reveals her understanding of what truly motivates her and allows her to welcome her future with open arms, implying that her key motivation is the pursuit of personal freedom and independence.
With respect to Jocint, the student may have confused the name with another character in the narrative. However, without a clear reference to Jocint in the provided excerpts, we are unable to accurately determine the phrase related to Jocint's motivation.