godan verb (-ru), intransitive verb
be greatly obliged; be very sorry
Formal, somewhat old-fashioned expression of deep gratitude or apology. Often used in set phrases like 痛み入ります.
お心遣い、痛み入ります。
I am deeply grateful for your consideration.
ご迷惑をおかけして痛み入ります。
I am very sorry for causing you trouble.
Standard kanji spelling.
Rarely used kanji form.
Compound of 痛み (itami, 'pain, hurt') + 入る (iru, 'enter'), literally 'pain enters'. The figurative meaning of feeling deeply obliged or sorry developed from the idea of being emotionally 'pierced' by someone's kindness or one's own fault.