unpredictable; no one knows what the future holds.

the future / future prospects

in the future

Eggcorn of 一寸先は闇 (issun saki wa yami, “unpredictable”).

one sun: a unit of length equivalent to a tenth of a 尺 (shaku, traditional Japanese foot as a unit of length), or approximately 3.03 centimeters / a short amount of time, distance, or mass

the dark, darkness

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend

dark, darkness