Usami is gentle and kindhearted, but also very naive and not very smart. While she is strict about rules and certain other things, it's very easy to trick or persuade her. All she wants is to foster love, friendship, and good manners, emphasized in her catchphrase "love, love!". Because of this, she can even come across overly sweet and annoying. She encourages everyone to live in peace and strengthen their bonds with each other. She is very happy and proud when everyone gets along, and scolds them when they do bad and kindly asks them not to do it again.
Voice reference: https://www.youtube.com/watch?v=tG2nwceuzs0