The emotion meter corresponds to the four vibe powers she has. The emotions at Vibe Island affect everybody, even enemies, while Peach can change hers at will. The four emotions are joy, gloom, rage, and calm. When the player taps on each mood it will activate a different ability that helps solve puzzles and defeat enemies. Each use will drain the player’s vibe meter. The bar can be restored by capturing blue turquoise jewels or absorbing enemies using Perry the parasol.

https://en.wikipedia.org/wiki/Super_Princess_Peach?wprov=sfla1