Gently-Colored Sunset Nanatsu iro doroppusu : Season 1 Episode 6

Starts with a flashback showing how Masaharu helps Sumomo go to her class. Sumomo falls in love with him after that day. Masaharu thinks Sumomo loves Natsume-sensei. Soon they meet up in the greenhouse to ask but the group arrive to help out. Later that night he transform and decides to talk to her via that form despite feeling guilty at the thought. She tells him that she loved Masaharu since that day. A star drop came and the couple arrives only for Nona to challenge them. During the fight she uses a freezing spell which her mother used but despite that she loses the duel and cries, none on the other hand despite winning she feels a sense of defeat. Masaharu learns that the quality of a spell depends on the emotions of the stellar speller and due to this he confesses his love for Sumomo at the greenhouse.