差し入れをお届けしたいとのことで


> お館様に内密で **差し入れをお届けしたいとのことで** 、私が鍵をお貸ししました

I don't understand this part. "To do X (without you knowing it), I lent them
my key" is all I can understand. I'm not satisfied with the translations I
found of 差し入れ and とのこと(で), it doesn't make sense when I try to put them
together.




「差{さ}し入{い}れ」 means a present (often, if not always, of food/drinks) and any
free online monolingual dictionary would have it as it is a very basic and
everyday kind of word.

「～～とのこと」 means "I am/was told ~~~."

> "I lent (someone) the key because I was told s/he wanted to secretly deliver
> a present to the lord/master."




「差{さ}し入{い}れ」 means a present (often, if not always, of food/drinks) and any
free online monolingual dictionary would have it as it is a very basic and
everyday kind of word.

「～～とのこと」 means "I am/was told ~~~."

> "I lent (someone) the key because I was told s/he wanted to secretly deliver
> a present to the lord/master."

