The Italian holds his debut season at Watford and in mid-March he was under pressure due to unsatisfactory results.
But later he managed to return the Hornet to the top half of the standings, and Mazzarri is confident that he will be at the helm of Watford and next season.
"I'm 100% sure that I will work here and next season," said Matzarri.
"I have a three-year contract, and something terrible must happen to me to leave".
Watford has won three of the last four Premier League matches and is ranked 10th in the standings for six games before the end of the season.