The oath comes first
An Affidavit is a statement you swear is true. In Messina you sign it in front of a notary, who checks who you are and then seals the sheet. That seal is the thing every later office looks at. So the honest answer to how to legalize an Affidavit begins at a notary's desk, never at a government counter. Nothing can be stamped before the oath is on paper.
Why the Procura and not the Prefettura
Italy splits this job between two offices. The Prefettura, the local arm of the state, handles papers from town halls and other admin bodies. A notary's act belongs to the other side, so it goes to the Procura della Repubblica — the prosecutor's office attached to the court. That is why consular legalization of an Affidavit in Italy runs through the Procura for the district where you swore it.
The mission that reads it
With the court stamp on, the file moves to the embassy or consulate in Italy of the country that asked for it. Their clerk reads the Italian stamps and adds one more. The embassy attestation of an Affidavit in Messina closes the chain, and each mission keeps its own forms, opening hours and payment rules. Book the slot early, because some desks open only two mornings a week.
Money and days
Set aside a €16 tax stamp (marca da bollo) plus the consular fee, which the mission fixes on its own. The usual clock to legalize an Affidavit in Messina runs 10–15 business days end to end. A rush route trims that to 3–5 business days where it is offered. Ask each desk how it wants to be paid, because several take a bank transfer and nothing else.
Who asks for one
Sworn statements travel for many reasons. People use them to declare a marital status, to confirm where they live, to name an heir, or to state that a lost paper cannot be replaced. Banks, courts and licence desks abroad all read them. Because the wording carries the whole weight, read your draft slowly before you swear it. One wrong date or a dropped middle name means starting the chain again.
Ask before you swear
Whether a consular stamp is wanted at all depends on where the paper is going, so put that to the receiving authority first. Some destinations settle for a single-step certification and say so plainly. If yours does want the full chain, confirm the required language with the receiving office in writing, and ask whether the translation is bound in before or after the stamps. Then the embassy legalization of an Affidavit in Messina can be planned in one pass.