For a moment, Watson didn't know how to answer that. He didn't know how to phrase I just wanted to make sure you were really here in any way that made sense, or sounded anything other than pathetic.

And then, quite simply, it dawned on him that the easiest thing to do was to answer Holmes's question honestly. It was the sort of logic that came easily in the middle of the night, in the madness of darkness. "I need to ask you a question," he said, rather slowly, picking his words with care. "And I need you to answer me honestly, whatever the truth might be. Can you do that for me?"