Final answer:
Jane is on the verge of accepting St. John's marriage proposal but is halted by a sudden realization that she cannot go through with it due to her internal conflict and true emotions.
Step-by-step explanation:
Just as Jane is about to accept St. John's marriage proposal, she hears her own inner voice and realizes that she cannot marry him. The tumultuous emotions she is experiencing are a result of her deep inner conflict between the sense of duty that pushes her towards accepting the proposal and her true feelings and desires that are in opposition. Jane's realization reflects a pivotal moment in her journey towards self-discovery and honesty in her relationships.