Focus on the pronunciation of certain
English definition of “certain”
/ˈsɜr·tən/ adj (KNOWING TO BE TRUE)
› knowing that something is true or will happen and having no cause to feel that it may not be true or may not happen; having no doubt: "I think Emily is going to pick up Judy." "Are you certain?" One thing is certain – supporters of the bill are not giving up. [+ (that) clause] I’m certain (that) he’ll be there. [+ question word] I’m not certain how much it will cost. When you report a robbery, make certain a police report is filled out (= check that this happens).