That if you confess with your mouth, "Jesus is Lord," and believe in your heart that God raised Him from the dead, you will be saved. For it is with your heart that you believe and are justified, and it is with your mouth that you confess and are saved. Romans 10:8-10

The Scripture means:

I can believe and stay quiet about it.

I can believe that Jesus is Lord, believe that He rose from the dead and be justified, but I need to tell someone.