This just struck me, but Jane's decision to accept Mrs. Elton's kind offices and engage herself as a governess mirrors Maria's decision to marry Mr. Rushworth after Henry's initial abandonment.

I mentioned in a previous post (linked below) my opinion that Jane Fairfax, in the height of anger and desperation, makes a last-ditch attempt to get Frank to confess his engagement to the Churchills.

We have already seen that Jane has pride when she tries to refuse generosity from Mr. Knightley (although she may have had added reason to do so).

After the miserable day at Box-Hill, Jane decided to close with Mrs. Elton's offer after learning that Frank left Highbury w/o attemting to reconcile with her. That seems to be a decision taken in the heat of anger.

In her first letter to Frank, she just dissolves the engagement. If she had any hope that this would induce Frank to "tell all" she is very disappointed. (I disbelieve Frank's confession that he "forgot" to post his reply to Jane). But by now, she is committed, so to speak, into Governessing. She could as easily have resolved to go and join the Campbells in Ireland. The words JA uses to describe Maria Bertram could well apply to Jane: She was in a state of mind to be glad that she had secured her fate beyond recall: that she had pledged herself anew to [Governessing]; her mind became cool enough to seek all the comfort that pride and self revenge could give.