tanto quanto io odio lei

as much as I hate her

→ tanto
phrase Rare #41,516
as much as I hate her The explicit subject pronoun io adds emphasis, while lei means “her” in this context. The phrase is grammatically understandable but somewhat emphatic; in ordinary Italian, “tanto quanto la odio” is often more natural.
IT: Lei mi odia tanto quanto io odio lei.
EN: She hates me as much as I hate her.

Lei mi odia tanto quanto io odio lei.

She hates me as much as I hate her.

Mi odia tanto quanto io odio lei.

She hates me as much as I hate her.

Mary odia me tanto quanto io odio lei.

Mary hates me as much as I hate her.

Odia me tanto quanto io odio lei.

She hates me as much as I hate her.