。
She's kind by nature.
Literal
She [topic-は] by-nature kind is.
生まれつき (うまれつき) means 'by nature' or 'from birth' — describing an innate quality. 親切 (しんせつ) means 'kind' or 'friendly.' である is the formal copula. The sentence states her kindness as a fundamental, inborn trait rather than a learned behavior.