It's a very confusing sentence, because we seem to have three women who take turns being the subject - Julia, Andi and Rusty's wife. When I first read this, it seemed to make sense, because I presumed that the subject of the second half was the same as the first. I had faith in the author's ability to put a coherent sentence together, so understood 'she' as referring to Julia. However, on my second reading I realised that it's meant to be Andi. The sentence would make more sense if it were written like this: Julia had told Andi about Rusty being arrested—utterly ridiculous—and so she knew his wife must be devastated, but hiding it well behind great makeup and a pretty dress with big patch pockets. It's still not a great sentence like this, but at least it's clearer what's going on. Note that I've deleted 'she was' before 'hiding'. This leaves us with a participle clearly referring to the wife. This removes the ambiguity about who 'she was hiding' refers to.

I would say it's mostly a case of lazy writing. Often times, when authors are dealing with several characters at the same time, they might omit the names or pronouns to avoid sounding repetitive or ambiguous. So they omit the subject and assume the reader can infer which character is saying or doing something. "and therefore knew" or "and she also knew" would be the best way to interpret it.

1) "(Julia had told Andi about Rusty being arrested) [—utterly ridiculous—] and (knew his wife must be devastated)" In my opinion:- The subject of BOTH the main clause AND the dependent clause is Julia. There is NO reason to say that the subject of the dependent clause is Andi. The two clauses are connected by a coordinating conjunction "and". These are not two independent clauses, so the dependent clause doesn't need a subject. 2) "and knew" = and therefore knew? There is no reason to require a "therefore"; the dependent clause is simply an addition of information logically parallel to the information in the main clause; it is not necessarily subsequent in time to nor logically dependent on the main clause . The dependence is merely grammatical construction.

Am I the only person who thinks that this is fine? Julia had told Andi (blah blah) and Julia knew that Rusty's wide wife must be devastated. Andi admired the courage of Rusty's wife. There is nothing wrong with any of this.

Reading for pleasure, or analysing by prescriptive grammar? That is the question to answer to deal with this messy sentence. From the sentence, does "she was hiding" refer to "his wife" or "Julia"; does "and knew" refers to "Julia" or "Andi"? does"her courage" refer to "Julia" or "his wife"? Are "Julia" and "his wife" one and the same person? Another thing......Is "and knew" a typo for "Andi knew"? This seems the most likely explanation, or is it?