The 55-year-old has seen doubts grow over his future despite a solid first campaign in English football, guiding the Hornets towards a top-half finish with six games to go.
Former Leicester City manager Claudio Ranieri is said to have been lined up by Watford's demanding owner Gino Pozzo to take over in the summer, but Mazzarri is adamant that he will not be going anywhere.
"As far as I am concerned I will be here 100% next season," he told reporters. "I have a three-year contract here and something terrible must happen for me to leave.
"We weren't very lucky with injuries and despite all this we are 10th. You only have to look at what the bookmakers said to know that is an achievement."
Watford, who have won three of their last four matches, return to action on Saturday afternoon with a trip to take on strugglers Hull City.