。
She paid personal attention to the matter.
Literal
She [topic-は] that matter [to-に] personal attention [object-を] paid.
注意を払う ('to pay attention') is the standard idiom for directing attention toward something. The English 'pay' metaphor crosses surprisingly well into Japanese 払う (which also literally means 'pay [a fee]') — the same physical-payment-of-attention image works in both languages. The に here marks the target of the attention, while 払う takes the noun 注意 as a を-marked object. 個人的な ('personal, individual') is built from the noun 個人 ('individual') plus 的 ('-like, of the nature of') and the na-adjective ending な.