Tone of voice plays a major role in getting a message across. It is very useful in expressing emotions or opinions. Curt,harsh,loud words can illustrate anger.
Soft,murmuring,soothing tones can express pleasure or bliss. A tone that rises in pitch at the end of the sentence indicates a question while one that is nasal and choppy can express irritation.
Whether you realize it or not,people develop much of their perception of you based on your tone of voice.
If your tone is clear , strong and full of exuberance , they may think you're confident.