If someone or something does a thing dependably, they do it in a way you can trust, again and again. The train runs dependably. She dependably sends the report on Friday. It is the adverb beside dependable, so it tells you how the action happens. It is a little formal; many people just say “always” or “you can count on it.” Though actually, you can use it with a smile when the thing you can “trust” is a small fault: he dependably forgets his keys. That is still the same meaning — you know what will happen.