(1) As you are one of the leading importers of pillow cases, we are contacting you in the hope of establishing business relations and rendering you assistance in a wide range of your requirements.

▲这里的render 意思是“提供；给予”(offer)，可以接双宾语。If you render someone help or service, you help them. 例如：

Any assistance you can render him will be appreciated.

无论给予他何种帮助，他都会非常感激。

If you'll deliver this parcel, you will render me a great service. 

如果你把这包东西送去，那就帮我的大忙了。

(2) The high reputation, which you are enjoying as camera importers, has rendered us desirous of entering into business relations with you. Accordingly, we introduce ourselves to you by sending you our catalogs and price-lists.

▲这里的render 意思是“使得；致使”(make)，可以接复合宾语（宾补由形容词desirous 充当）。You can use render with an adjective that describes a particular state to say that someone or something is changed into that state. For example, if someone or something makes a thing harmless, you can say that they render it harmless. 例如：

His remark rendered me speechless.

他的话使我哑口无言。

It contained so many errors as to render it worthless.

太多的错误使之变得毫无价值。