The Italian word for 'no' is spelled and pronounced exactly the same as in English.
In fact, you may find that the word for 'no' is very similar in many languages.
The word 'no' in different languages
The word 'no' in France would be written non (with the final 'n' silent, and the 'o' sound nasalized) although, in the the Alsace region of France, people might opt for ne- which is incidentally the same way 'no' would be written in Cameroon, Bulgaria and various countries of former Yugoslavia including Croatia, Serbia and Bosnia & Herzegovina.
Mhai is the Cantonese version, whilst Mandarin-speakers will tell you Bu shi zhe yang or just Bu shi for short.
Some languages that you may be surprised to find share the English 'no' are Catalan, Bislama, and Kurdi, and if you're looking to do some further research, why not check out this list of the word 'no' in more than 520 different languages.
Yes in Italian
The Italian word for 'yes' is sì, and if you're unsure you may want to use the word forse meaning 'maybe'. For 549 other ways to say 'yes' in several languages, why not follow this link.