This is the 35th most frequent Italian word.
non
"Non" means "not" in English.
Here, 'non' is used in the phrase 'non solo' to indicate 'not only'.
Non solo è intelligente, ma è anche simpatico.
Not only is he intelligent, but he is also nice.
Here, 'non' is used to negate the noun 'la verità' in juxtaposition with 'una bugia'.
Hai detto non la verità, ma una bugia.
You said not the truth, but a lie.
Here, 'non' negates the verb 'voglio', meaning 'I do not want'.