Answer:
graciously accept the blame for not making her meaning clear.
Explanation:
In business communication when the message being passed is not clearly understood for one reason or the the other (in this case because of language barrier). The polite action to take is first to graciously accept blame for not passing the message across clearly, then find a solution to the communication gap.
Talking louder to the other party will be the wrong step to take as it will appear rude, so offer an apology which will give a positive environment.
The other options of ending the conversation and asking an Italian business man to explain what you mean in simple terms will be taken as a slight.