Reliability or dependability stands for how well a professional or a business honor their given word or agreements and how well they meet expectations — what is automatically expected of them just as of any other reliable and solid business, e.g. to be honest, discreet, flexible, diligent, without serious conflicts of interests, law-abiding, communicative and so on.
So there are two levels of reliability: 1. the explicit level, which we’re all aware of and which lies in keeping one’s given word or honoring agreements, and 2. the implicit level, which lies in fulfilling that which is expected of a true professional or solid business.
One of the major goals of good process management is to boost one’s levels of reliability to the maximum, i.e. to be predictable and dependable in the broadest sense.