arm and leg? what is this? Is this formal expression?

[kwfine]

Dear teachers,

I sent out some job application forms to a few companies respectively a month ago,
and recently I received two offers from them (one from a Chinese company).

I was confused by the reply in one of the offer letters though:

"I am happy to have received your letter Ms.xxx, and it seems to me
you are the one I have been looking for a long time.
I hope you can be my arm and leg for my business operation..."

What is "arm and leg"?
Is this formal expression?
I have looked it up in my Oxford dictionary but I
couldn't find any idiom or expression that give me hints of what it means.

Please help, teachers.

Thank you.
Kitty.

[bhaisahab]

Dear teachers,

I sent out some job application forms to a few companies respectively a month ago,
and recently I received two offers from them (one from a Chinese company).

I was confused by the reply in one of the offer letters though:

"I am happy to have received your letter Ms.xxx, and it seems to me
you are the one I have been looking for a long time.
I hope you can be my arm and leg for my business operation..."

What is "arm and leg"?
Is this formal expression?
I have looked it up in my Oxford dictionary but I
couldn't find any idiom or expression that give me hints of what it means.

Please help, teachers.

Thank you.
Kitty.

Well, it's very strangely worded. I would guess that he means to say that you could be "the arms and legs" of his business. Which suggests that he wants you be responsible for everything to do with the day to day running of the business.

[Raymott]

Dear teachers,

I sent out some job application forms to a few companies respectively a month ago,

See the recent threads on "respectively".

[Jaskin]

Hi
Please note not a teacher nor a native speaker,

I've heard the phrase "to cost an arm and a leg" witch means "cost a great amount of money" but it doesn't seem to fit in that context.

Perhaps it's a word by word translation of an idiom in the writer's mother tongue.
I catch myself making such translation.

Cheers

[BobK]

... but Jaskin probably knows it's 'which'.

I agree with bhaisahab, and with Jaskin's guess that it may be a word-for-word translation of an idiomatic expression in the user's mother-tongue. We don't have an exact translation (as an idiom) for the intended meaning, but we do have the idiomatic expression 'eyes and ears''. It would be perfectly idiomatic to write 'I want you to be my eyes and ears...', but that is less 'hands-on' than the writer seems to mean here.

b

[Tdol]

My right-hand man?

[Helenochka]

I tend to back up Tdol's opinion. Probably, they want to underline how supportive and helpful you might be. It comes from the context.

[joham]

I'm Chinese. I agree with Tdol. The boss intends to employ the applicant as an important subordinate. But we can see that the boss himself, or someone who was writing this letter for the boss, doesn't know much English and was doing a word-to-word translation from a very informal spoken Chinese expression which was used in this context perhaps in order to show friendliness and trust. Even so, it sounds inappropriate to my Chinese ear.

[susiedqq]

I have heard:

right hand person
eyes and ears in the company
leg man
front man
hands and feet


I am sure he meant "close assistant."

[Anglika]

I think he meant you would be his "right-hand man", the person on whom he can rely to get things done.