When someone does not understand what you say how do you apologize and say that it was your fault? Sometimes when we are trying to help our customer by giving directions or guidelines, and the customer does not seem to understand what we we are saying and looks very confused, is it right to say "I'm sorry I couldn't make it very clear. Let me repeat it for you."?
There is no set phrase like "bless you" when someone sneezes for this situation.
Your phrasing is fine. However I think instead of "repeat" you might indicate that you will "rephrase". If the customer doesn't understand, just repeating won't help them!
Perhaps I could be clearer. Let me say that a different way.
Avoid apologising too much, it can seem sarcastic and passive-aggressive.