It's always tough writing about a performance when you don't feel the song. With that in mind, I'll comment in generalities for Demi Lovato's live rendition of Confident at the 2015 AMAs.
The staging was good, with some great lighting driving the energy. Demi wasn't a slouch either, selling the song's message with confidence and attitude. But that would all be for naught if she flopped on the vocal front.....which she didn't! The lowest notes were a little iffy but the rest was really good, with the Diva delivering her signature brand of edgy belting. Interestingly, she didn't inject as much weight into the belt as we've heard previously, but that was a smart choice, making the top notes sound healthier and easier.
Her second performance of the night was with Alanis Morissette, where they sang You oughta know. This wasn't as good a showing for Demi, though Alanis was sounding great. I just wished the American Music Awards had allowed the Diva to sing her own song, solo, since Demi was clearly holding back out of respect. A choice that made the duet stiff and unnecessary.