Which of these characters in "Undertale" can the player NOT go on a date with?

The player cannot go on a date with Toriel in Undertale because she is the first major character introduced in the game and serves as a mentor and guardian to the protagonist. After the player encounters Toriel during their journey, there is an option to choose a pacifist route where the player can spare all the enemies and befriend them. However, Toriel's role as a caretaker and guardian prohibits any romantic relationship from forming between the player and her. Additionally, her character arc focuses on guiding the player rather than developing a romantic connection.