I disagree with you.
'D'accordo' — dac-COR-do. Contraction of 'di accordo'. The 'd' and 'a' merge — say it as one word. Stress on the second syllable.
Use to politely but clearly disagree. 'Non sono d'accordo' is direct without being aggressive — the standard way to express disagreement in Italian.
'Essere d'accordo' (to be in agreement) is the standard Italian phrase for agreement. Negating it gives disagreement. It's more direct than English 'I'm not sure I agree' but less confrontational than 'hai torto' (you're wrong).
Non la vedo così.
I don't see it that way.
Softer disagreement — 'vedere' (to see) implies a different perspective, not a conflict
Ho una visione diversa.
I have a different view.
Formal — used in professional discussions to flag diverging positions diplomatically
Permettimi di non essere d'accordo.
Allow me to disagree.
Formal and polite — signals respect for the person while disagreeing firmly
Italians disagree openly and passionately — this is not considered rude. Animated disagreement is part of the Italian conversational culture. What matters is that disagreement is argued with reasons, not just stated flatly.