“For the Spirit God gave us does not make us timid, but gives us power, love and self-discipline.” - 2 Timothy 1:7
We have a spirit and it comes from God. From serving God, not ourselves. We walk with God and learn about Him by reading the Bible. He begins to talk to you with a distinctive voice. You can hear Him answer your questions. And yet you doubt too. How much is it His voice, and how much is it you wanting it to be His voice? Walk with God by reading the Bible. He will tell you.
You cannot fail. God loves you. Hold to His purpose, and He will reward you. What would you do if you knew you could not fail? What holds you back? He will open the doors if it is His will. But you must knock on the door, too. Let Him say yes. And accept it if He says no.