The phrase
"unclear passages" refers to parts or sections of a text that are difficult to understand or not clearly explained.
Full definition
It's a basic hermeneutic principle of Scripture called «the analogy of Scripture,» where we
interpret unclear passages in light of what is clear.
The married couple apparently split up after
an unclear passage of time; the other woman dances joyously on the beach while completely nude before lying on the sand; the wife does a more somber dance while also in the buff, then finds the other woman lying there.
Another individual could be able to detect
the unclear passages or errors that you, as a writer, fail to notice due to your knowledge of the material being intimate.
She doesn't try to rewrite you, but does point out mistakes (which for a non-native speaker are almost natural, sigh) or
unclear passages.