understanding, comprehension / appreciation

one's heart, one's feelings

difficult / hard, probably impossible

understand, comprehend / appreciate

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

impossible to understand, utterly confused

everything

(slang) Alternative form of 彼氏 (kareshi, “boyfriend”)