I think JA primes the reader for this meeting right from the first reference at the end of ch.3:- ".... he, perhaps may be walking here." Every time the subject of FW comes up in chapters 4-7 we see Anne's unquiet emotion, often expressed in physical terms:- "the comfort of cool air for her flushed cheeks", "pain", "agitation", she must "harden her nerves".

The meeting with Mrs Croft in ch.6 delivers several jolts:
"It was you ... that my brother had the pleasure of being accquainted with.." - Anne does not actually blush, but the emotion is seething away inside her.
"Perhaps you may not have heard that he is married.."(!!!) - It turns out that it is brother Edward who is married (Phew!!! That one's a real kicker!)
"We are expecting a brother of Mrs Croft" (Is it Edward? Or is it Him??) It turns out that it is him - Frederick is coming! The ensuing conversation about poor Richard and Captain W is a "trial to Anne's nerves".

The tension continues to build through chapter 7. Twice Anne is relieved to "escape" a meeting with CW. A double dose of "raptures" about him from the girls piles on the pressure. Left alone with the little boy, Anne's attempt at indifference - ".. and what was it to her, if Frederick Wentworth were only half a mile distant, making himself agreeable to others!" - is futile. All she can think of is him, and how he feels about meeting her.

Then the tension is ramped up still further: He is coming to breakfast (!!) ... but not at the Cottage (Phew!!) He wants to avoid seeing her... wants to escape the embarrassment of an introduction.
Anne is already almost vibrating with tension, then he arrives almost without warning.
The paragraph beginning "The morning hours of the Cottage..." is one very long sentence, Charles speaking very quickly, a string of terse, pared-down phrases that really kicks the pace up and induces a sense of things suddenly happening very fast.

As for the encounter itself, Mara likens it to a film script and I partly agree, but I find the prose even more intimate. The reader has the illusion of actually inhabiting Anne and experiencing things as she does. She cannot look at him, cannot speak; she can hear but cannot make much sense of what is being said. You share the mental turmoil, and can almost feel her inability to breathe normally. To convey this on film might involve putting Anne's heartbeat on the soundtrack, suddenly increasing in speed and intensity from the moment when Charles says Captain Wentworth is coming, practically drowning everything out while he is in the room, and gradually slowing and fading through "It is over" It is over!.....The worst is over!"

Here the prose gradually reverts to longer, measured sentences, and the emotional temperature subsides to relative normality. Phew! It's stirring stuff.

Charlotte Bronte wrote of JA's work: "... the Passions are perfectly unknown to her; she rejects even a speaking acquaintance with that stormy Sisterhood; even to the Feelings she vouchsafes no more than an occasional graceful but distant recognition". (letter to W.S. Williams, 12 April 1850)
On the basis of passages like this in "Persuasion", I have to say that I do not agree with that assessment!

By the way, you are by no means the last to pick up on this matter of JA's style in "Persuasion", Cheryl! When it comes analysing, or even noticing, literary technique I'm plodding blindly along behind you. When I read I just swim through the words, swept along by the illusion, and simply don't notice that is is an illusion or the mechanics of how the effect is created, so I'm very glad to have stuff like this pointed out.