The phrase "a certain sum of" is correct and usable in written English.
It can be used when referring to an unspecified amount of money or resources.
Example: "The company agreed to pay a certain sum of money to settle the dispute."
Alternatives: "an unspecified amount of" or "a particular amount of".
Of course, you have to leave a certain sum of money for your instructions to be taken seriously.
You would pay them dollars (or whatever currency) for a certain sum of Liberty Reserves, which they would then deposit into your account.
A leader is told that his area must achieve a certain rate of GDP growth, attract a certain sum of inward investment and increase government revenues by a specified amount.
An individual, usually a woman, would fall into a kind of wasting illness, until her relatives agreed to "hire, for a certain sum of money, a band of trumpeters, drummers, and fifers, and buy a quantity of liquor; then all the young men and women of the place assemble at the patient's house," where they dance and generally party for days, invariably effecting a cure.
Bill of exchange, also called draft or draught, short-term negotiable financial instrument consisting of an order in writing addressed by one person (the seller of goods) to another (the buyer) requiring the latter to pay on demand (a sight draft) or at a fixed or determinable future time (a time draft) a certain sum of money to a specified person or to the bearer of the bill.
It has been defined in England as an unconditional order in writing addressed by one person to another, signed by the person giving it (the drawer), and requiring the person to whom it is addressed (the drawee) to pay on demand or at a fixed or determinable future time a certain sum of money to, or to the order of, a specified person (the payee) or to the bearer.
Mr. Sharma will also be given a certain sum, known as "gratuity"— a token of gratitude for decades of service.
In the case of the perpetuity, the undertaking is to pay a certain sum each year or other interval of time for the indefinite future.
A bond with a date of maturity usually involves a promise to pay a certain sum each year for a given number of years, and then a larger sum on the terminal date.
I drew a sketch of the plan and rules that would be necessary, and got a skilful conveyancer, Mr. Charles Brockden, to put the whole in form of articles of agreement to be subscribed, by which each subscriber engag'd to pay a certain sum down for the first purchase of books, and an annual contribution for increasing them.
And, generally, no court enforces oral agreements of any kind above a certain sum.
