You can’t guarantee. But you can look at a candidates statements and the history of the party they represent, to get an understanding of what will happen.
When one candidate says “I’ll only be a dictator for one day” and his party doesn’t react to this statement, that’s a pretty big red flag that your civil rights will be severely eroded if they get into power.
I’m not upset when someone uses their democratic right to vote for the person they want.
I’m more upset that we live in a society where people see a person that wants to take away their democratic rights and thinks “Yup, that’s the one for me”.