Is This Sentence Correct?

"to be of assistance" is a somewhat formal expression that means "to help".
You can say, "I am glad that I was able to help at the party".
Or you can say, more formally, "I am glad that I was able to be of assistance at the party".

So "being of assistance" means "helping".

We look forward to [helping / being of assistance] in addressing ...

The sentence is correct.

CJ

It may be correct grammatically, but it is unnecessarily complicated. Much better to say something like "We look forward to helping you address the diagnostic needs of your organization."

Thanks for your response,

But query still exist in my mind.

1) How can I know that I have to add being ? Is word "being" in this sentence make the word "assistance", noun / verbal noun.

2) I am glad that I was able to be of assistance at the party". - can we write this sentence in "being" form.

3) to be of help means to help - But be of confuses me. Likewise being of assistance means helping - How ??

Hope you can understand, where is the problem.

I think "being of assistance" means "you can ask us for help any time you want/need"

while,"we look forward to helping you" is not vey good.Beause it means "we hope that you should meet difficulties as soon as possible,so that we can help you"

look forward to =hoping to do

be of = have/has

eg"it's of no importance= it has no importance

Dear friends,

It is my opinion that we may say «I look forward to being of assistance» if we wish to be deferential.

It is also my opinion that we may say «I look forward to helping you» if we are confident that we will be asked to help.

But it is only my opinion.

Kind regards,

Goldmund

Is [the] word "being" in this sentence [used to] make the word "assistance"... [ a ] noun / verbal noun [?]

No. The word "being" is used because it is the gerund form of "to be". A gerund form must follow the expression "look forward to".

I am glad that I was able to be of assistance at the party". - can we write this sentence in "being" form [?]

No. Unlike "look forward to", the expression "to be able" (in the form "was able" in this sentence) must be followed by an infinitive ("to be"), not a gerund ("being").

be of confuses me

Yes, it is confusing. A form of "to be" followed by "of" and a noun is usually equivalent to "to be" followed by an adjective of similar meaning. It is an idiomatic use of an "of" phrase. Here are some other examples.

to be of use = to be useful
to be of help = to be helpful
to be of importance = to be important
to be of significance = to be significant
to be of consequence = to be consequential
to be of interest = to be interesting
to be of assistance = to be helpful (because there is no word "assistanceful"!)
to be of worth = to be valuable (because there is no word "worthful"!)

CJ

Thanks