When do you use the expression "How could it be"?
"How could it be" here is actually referring to the fact that the speaker was wrong. You can understand it as meaning "how could it be (that I was wrong)?" or "how is it possible (that I was wrong)?" You can use it in similar situations to indicate your disbelief at something that has happened, or when you want to question how something has happened. Ex: We failed our group project. How could this be? Ex: How could it be that we left the house early, but still arrived late to the event?