Alec seemed to sigh a breath of relief and he believed her. There was no need to suspect her of anything - people were generally honest, after all. Okay, well, he was fibbing a little - but only a little! And only because he knew how it looked, but it wasn't like he'd ever do anything. He would just admire Mary from afar.
"Thank you." He meant it. "I should... I need to get some groceries. So I should probably go." Plus he didn't want to stay in this aisle any longer than absolutely necessary.