Complex sentence: When Sakura was introduced, Kishimoto did not think of her as Naruto's future wife, although once Hinata had appeared, the author thought of forming a love triangle between the three characters.
Split into simpler sentences: When Sakura was introduced, Kishimoto did not think of her as Naruto's future wife. However, once Hinata had appeared, the author thought of forming a love triangle between the three characters.