。
She's not just cute, she's kind too.
Literal
She [topic-は] cute [not-only-だけでなく] kind also-is.
The ~だけでなく ('not only') pattern is paired here with a でもある ('is also') completion. The でもある construction is built from the copula で + も ('also') + ある ('exist'), giving 'is also.' It pairs naturally with predicate nouns and na-adjectives (親切でもある, 努力家でもある). The whole structure 'X だけでなく Y でもある' is a clean way to layer two predicate qualities in a single sentence — slightly more formal-sounding than X だけでなく Y もいい.