Understanding and assistance _______ much appreciated.

Does anyone help with the use of

Understanding and assistance _______ much appreciated.

Can I use "is" "are" "would be" after the word "assistance".

Use "are" - there are two subjects.

Oh, "would be" sounds fine to me as well.

Understanding and assistance _are______ much appreciated.

Your understanding and assistance are much appreciated.

Your understanding and assistance would be much appreciated.

Your understanding and assistance is much appreciated.

So, it is different tenses.

are: present tense

would be: future tense

is much: past tense

Your understanding and assistance have been much appreciated.

I don't think 'is' much appreciated, is the ideal formulation. But it is quite noticeable that English Newsreaders often make mistakes in tense. However the meaning is quite clear.