dimwitted, slow

dimwit, simpleton, dunce

short for 鈍色 (nibiiro): dark gray

(of edge) dull, blunt / (of senses) dull, stupid, slow, slow-witted

a blunt blade / a lazy person, a dullard

(uncommon) dull of edge, unable to cut well / (uncommon) dull of mind, lazy, insipid

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

(と〜) thinking that […] (with the next clause explaining that the truth is contrary to expectations)