When the idea of a reliable voice comes to mind, the first word that comes to mind is trust. A voice you can trust all all that it has to say, and trust is something practically every person is looking for.
How does a voice become reliable? It is a voice that first of all sounds familiar in some way, whether we have heard it before or not. It is familiar in its tone, pronunciation and is above all speaking in a manner that is clear and straightforward, a manner that the listener gets an impression it can really depend on. Very often, it is a voice by a person the target audience is already familiar with - an actor, musician, artist or a known personality from other fields of life. Yet, sometimes, the voice just simply sound familiar and can instill reliability.
Whenever we need to present a complex idea or an idea that might be hard to accept, the potential audience would surely love that it is explained by a reliable voice. The same is also true when we need to present a completely new product or one that has not been fully accepted yet. Any audience that needs to have trust in what it is hearing/viewing is more prone to accept it if it hears a voice that sounds as it comes from a person they can rely on.
The key word with the sound of reliable voice is familiarity. While its pitch and tone can vary, as long as the target audience cany relate to it an immediate connection is made. Yet, a reliable voice sounds straightforward and direct, s it is speaking with a family member, a good friend or a neighbor they alredy know for a while.