。
It's my opinion that she's right.
Literal
She [topic-は] correct is [quotative-という] [subject-のが] I [possessive-の] opinion is.
~というのが私の意見です literally means 'the fact that ~ is my opinion.' という nominalizes the preceding clause, の further nominalizes it, and が marks it as the subject of 意見です. This is a formal, somewhat stiff way to state an opinion — more natural in written or academic contexts.