、。
She had no illusions about her own looks.
Literal
She [topic-は] her own appearance [as for-については], misconceptions [contrast-は] was-not-doing.
The outer は marks 彼女 as the matrix topic; the inner は in 思い違いはしていなかった is contrastive, splitting 思い違いをする into 思い違いは + していなかった to emphasize 'misconceptions specifically — those, she wasn't having.' Inserting contrastive は into a noun-を-する compound is a productive Japanese pattern that strengthens negation. 思い違い ('thought-mistake') = a misconception or wrong belief; ~については ('as for X, regarding X') topicalizes the domain.