肝胆 かんたん あい らす
kantan'ai terasu

Godan Verb (su)
Expression

1. to be profoundly compatible; to be inseparable; to be so close as to reveal to each other the bottom of one's heart

かれとは学生 がくせい時代 じだいから肝胆 かんたん あい らす なかだよ。
karetowa gakusējidaikara kantanshō terasu nakadayo.
He and I have been inseparable friends since our student days.
Other forms: