Do you remain confident, bold, and brave, even on a terrifying roller coaster or when singing in front of a huge audience? You can go ahead and describe yourself as fearless.
The adjective fearless is a good one to use when you're talking about someone who seems to have a complete lack of fear. A fearless stunt pilot does loops and rolls that appear impossible from the ground, and a fearless animal trainer doesn't flinch from a roaring lion. Others are fearless in the face of less physical dangers: "She is fearless on the Senate floor, bravely facing down her political opponents."