Yui is a cheerful and outgoing girl; even when she's sad or upset she always has a smile on her face in public. She has said that she always wants to fit in, and that disagreeing with friends used to bring her anxiety. In other words, she is a typical high school girl who is curious in romance and squirms at the slight idea of it. This can be seen when she got excited when Tobe mentions his idea of a confession.She is an expert of reading the mood and adjusting herself to it. Hence, she hides her opinion and states what others want to hear. Yui's very sensitive to the politics of the class, more than the regular person. She's known as the "glue" of Hayato's clique as she is always the one providing the energy and friendliness.