There are a few tutorials online that talk about Column Level Security but they seem complicated to me, another way of accomplishing this is to create a trigger function that will always set the isVerified column back to its original value each time a update is made. Since this would be using a SQL query you could create another function to check who the user is before making this change, in case you want to allow like an admin to change that field but not the user or any regular user's themselves