HAVE you ever written “Your kind assistance is highly appreciated”? Were you requesting help or acknowledging help already given? This sentence is thanking the reader for his/her assistance, not requesting it.
If you are requesting assistance, then it is appropriate to use the conditional form “would be”, otherwise the statement could appear presumptuous. Thus, the form would be “Your assistance would be highly appreciated”. Drop the “kind”; there is no need to kow tow. Courtesy does not equate with obsequiousness.
