The only way you can be sure that it is His voice you are hearing is to hear it so often that a
stranger's voice is instantly recognizable. It is far wiser to spend time learning the One True Voice than it is trying to learn to detect a multitude of false voices. Do you know the voice of the Lord?
"Hearken unto Me now therefore, O ye children, and attend to the
words of My mouth." Proverbs 7:24