SKEPTICAL

Skeptical : Meaning : in doubt or unwilling to believe 
Many a times you aren't sure about something, which means, you have some doubt about it. 
If someone tells you something that you aren't willing to believe, that means you are skeptical about what is told to you. being skeptical basically means to be in doubt about something or you are not believing it. 
If you are skeptical about something, you are always in two minds, for example, whether is it possible or is it not possible, OR is that true or not, can I fulfill a particular commitment or not ? 
In short, it leaves you feeling very unsure about something. 
You are often skeptical before making big decisions in your life, such as deciding which career you should opt for. 
That means you are not sure or you are in doubt about the choice you make. 
When it's difficult or hard to believe something or someone, you are skeptical, you are unwilling to believe or you doubt something. 
As the word 'sceptical' describes a person's feeling, it is an Adjective.
Example sentences 
Ex 01 : They say that apples clean your teeth, but I'm skeptical about that as I doubt it is true. 
Ex 02 : The employees are very skeptical about the change in the Management. 
Ex 03 : The doctor is skeptical about his patient's recovery, as the medicines are not helping any longer. 
Ex 04 : I'm skeptical about the food served at this restaurant, the vegetables don't seem fresh. 
Ex 05 : Despite all the promises made by the politicians, the public is always skeptical while casting their votes. 
Ex 06 : Due to continuous arguments, Sam and Mary were very skeptical about getting married, but they finally pulled through. 
Ex 07 : I don't believe in fortune tellers, I'm very skeptical about their predictions. 
Ex 08 : Due to the heavy rainfall and flooding in the city, the parents were very skeptical about sending their kids to the school.