【形式ばった表現】 commit an inexcusable blunder
申し訳に
…の申し訳に
to excuse 《one's mistake》; 【形式ばった表現】 in excuse of…
〈罪の償いに〉 【形式ばった表現】 to atone for 《an offense》; 【形式ばった表現】 in expiation of 《one's past sins》
ただほんの申し訳に
【形式ばった表現】 perfunctorily
I must apologize.
申し訳ないこと
Excuse me, but...
I am terribly sorry but,
I really don't know how to apologize to you.
I'm sorry to trouble you, but …; Excuse me, but ….
Pardon me for interrupting you.