。
She behaves as if she were raised in a good family.
Literal
She [topic-は] good-family [at-で] was-raised as-if acts.
かのように ('as if, as though') marks a hypothetical comparison — the sentence implies she was NOT actually raised in a good family but acts like she was. This is stronger than のように, which could be either literal or hypothetical. 振る舞う (ふるまう, 'to behave, to conduct oneself') is the standard verb for describing someone's demeanor.