"In that direction only pain lies" suggests that pursuing certain paths or ideas may lead to suffering and hardship. It reflects a perspective of caution, warning against venturing into areas that could bring emotional or physical distress.
The quote, from John Boyne's "The Absolutist," emphasizes the idea that some choices or pursuits might result in unavoidable pain, highlighting the struggles faced in life or certain decisions. It serves as a somber reminder of the difficulties that can accompany difficult journeys or truths.