Florence Foster Jenkins, a soprano, loved to sing—especially the great operatic classics. She inherited money when she was in her 50s, which funded her musical career. It wasn't long before her popularity skyrocketed, holding annual recitals at the Ritz-Carlton in New York throughout the 1930s and 40s. But as one writer puts it, "History agrees, with hands held over its ears, that she couldn't sing for sour apples. Jenkins' nickname, behind her back, was 'the Tone-Deaf Diva,' or 'The Terror of the High C's.'" The writer adds that if you ever hear one of her old recordings, all that you'll hear will be "squeaks, squawks, and barks."

But get this: she didn't ever grasp that she was bad! When people laughed and hooted as she sang, she took it to be delirious enthusiasm for great music. She thought they loved her and her music.

In 1944, when she was 76-years-old, she did a benefit concert for the armed forces at Carnegie Hall in New York. Thousands lined the streets to get tickets, and the performance sold out in minutes. The recording of that concert is still the third most requested album from Carnegie Hall recordings, punctuated by a painful rendition of "Ave Maria."

What can we learn from Ms. Jenkins? People will say, "It doesn't matter what you believe, so long as you're sincere." But it does matter. Belief must match reality, or it is laughable, a delusion.