(literary) Alternative spelling of 思い出す

difficult / hard, probably impossible

to think, to consider, to believe

to recall; to remember / to guess; to conjecture

ancient times, a very long time ago

once (in the indeterminate past)

the past, old times / ancient

olden days; former

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