In the Anime she's more selfish than her visual novel counterpart, for example it's implied she had an ulterior motive to get together with Makoto anyway, ignoring Kotonoha while in the VN she only does so if Makoto genuinely proclaims his love. She also concerned less with the well being of others, such as Kotonoha being cheated on, and further she doesn't break off things when Makoto starts to cheat on her. However she does attempt to stop the affair early on after she realizes the damage she has done and tells Makoto to leave her alone and stay loyal to Kotonoha. However Makoto convinced Sekai that he loves her more and implies that he broke things off with Kotonoha.