、、。
Sado-san has a charming personality, but she doesn't realize its value and dislikes herself.
Literal
Sado-san [topic-は] charming personality's owner [despite-なのに], that value [subject-が] not-understanding [classical-ず], self [object-を] doesn't-like.
Three structural elements to point out. 持ち主 ('owner, possessor') is the set expression for 'one who possesses X' — built from 持つ ('hold') + 主 ('master/subject'). なのに ('despite,' 'even though') attaches to a noun-predicate with the intermediary な, expressing unexpected contrast. 分からず is the classical/literary negative converb of 分かる ('without understanding') — the modern 分からないで would be the everyday equivalent, but ず is preserved in written and slightly formal speech.