That depends upon the subject that is to be believed in....
When it came to women I was a skeptic... But when it came to my wife... I was a believer before I could be a skeptic... I had a promise from the Lord already and was waiting for it to be fulfilled... she was that answer and I knew it before I ever saw her face or photo. We have now been married 12 years and have two kids... as they say.. "The proof is in the puddin."
In Religion I first believed by accepting the teaching as a child... But after falling away from the church for many years I was a very mixed up person who had to make sense of what to believe... Because of this I spent years of "Testing God" and eventually proved him through the Evidences of Faith.
(Hebrews 11:1 Now faith is the substance of things hoped for, the evidence of things not seen.)
He always Rebukes Sin and has Mercy upon us when we Confess and forsake the sins... He is testable... if a person has the patience and truly desires to know him... He will reveal himself to you.