English term (edited): in an arm's length transaction

it is said of a transaction negotiated by unrelated parties, each acting in his or her own self interest; also a transaction in good faith in the ordinary course of business

English term (edited): in an arm's length transaction

it is said of a transaction negotiated by unrelated parties, each acting in his or her own self interest; also a transaction in good faith in the ordinary course of business by parties of independant interests

English term (edited): in an arm's length transaction

However, more context is needed.

http://www.socpa.org.sa/AS/as16/as1605.htm

والله أعلم

The concept of an arm's length transaction commonly comes into play in the real estate market. When determining the fair market value of a piece of property, the price for the property must be obtained through a potential buyer and seller operating through an arm's length transaction, otherwise, the agreed-upon price will likely differ from the actual fair market value of the property.

For example, if two strangers are involved in the sale and purchase of a house, it is likely that the final agreed-upon price will be close to market value (assuming that both parties have equal bargaining power and equal information about the situation). This is because the seller would want a price that is as high as possible and the buyer would want a price that is as low as possible.

This contrasts with a situation in which the two parties are not strangers. For example, it is unlikely that the same transaction involving a father and his son would yield the same result, because the father may choose to give his son a discount. (http://www.investopedia.com/terms/a/armslength.asp)
Based on the above, I think that the translation I am suggesting would be an acceptable one...although in specialsed translation one can never be 100% sure!