、。
She isn't just pretty — she's clever as well.
Literal
She [topic-は] pretty [not-only-ばかりでなく], clever is.
The pattern ~ばかりでなく ('not only X...') is a written-leaning version of ~だけでなく, both meaning 'not only X, but also Y.' ~ばかりでなく carries a slightly more formal or literary register and is common in essays, news, and formal writing; ~だけでなく feels everyday. Often the second clause has も ('also') to mark the additional element, though it's omitted here. 利口 ('clever, smart, shrewd') is a slightly old-fashioned word — common in older novels and 19th-20th century usage; modern equivalents would be 賢い ('wise') or 頭がいい ('smart').