Kioku no tabidži (S02E17)

As she attempts the first trial, Emilia finds herself in Elior Forest, where she lived when she was younger. Echidna snidely remarks on her audacity to set foot here after so thoroughly disgracing herself before, but Emilia responds with a bold smile and tells her she won't cave to the malice of a fellow witch. As they proceed deeper into the forest, they come upon a massive tree towering over its surroundings. At its base is a small, barred door, which Emilia identifies as the Princess Room where she was often sent to play as a child. (Crunchyroll)