While her appearance on The Voice was actually a promotional campaign for her band The Kitchenettes, she seems to have taken a liking to solo projects and, of course, she also got a record deal, to which obligations are attached. She has mastered this perfectly with The Fool and her soul voice belts out the song with a sixties sound.
Here is a live version....
The song has a classic structure and tells us how stupid she was to believe "his" promises and that it's over now. May he please go to hell. Anyone who doesn't like to sing along and maybe even has someone in their sights....
When listening, you can pay attention to the triangle in the background or the low strings. Logically, the soundboard masters these sequences "easy peasy" - even in loud.