As uncomfortable as it must have been, I just can't see Emma trying to sugar-coat the issue. She certainly wouldn't have tried to fabricate a story about another woman! Nor would she sully her beloved Mr. Knightley's name by implying that he was cherishing "reprehensible feelings" for a married woman. The truth must come out sooner or later, and to compound the pain by lying about it is not in her character. Emma has her faults, but dishonesty isn't one of them.