。
She can't see her own beauty.
Literal
She [topic-は] her own beauty [subject-が] is-not-being-visible.
見える ('to be visible, can see') is a stative/spontaneous verb of perception — visibility comes to the perceiver rather than being deliberately sought (compare 見る 'to look at,' 見られる 'to be able to see (potential)'). With が marking the thing visible and ~ていない negating the resultative, 見えていない frames her beauty as something that, to her, is not registering — different from 気づいていない ('hasn't noticed'): 見える suggests the thing is right there but isn't perceived as such.