Characters
It's only forever, not long at all.
— Jareth · Labyrinth

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
The line puts the endless span of forever beside the claim that it is not long. That deliberate contradiction creates its humour and strangeness. Depending on context, it could sound reassuring or unsettling, but the words themselves playfully minimise an immeasurable stretch of time.
Context reviewed