How to correct these into natural English

You can say it however you want in the second half...but the first half should read, "I don't think both of our companies...have been ..."etc.

Thanks! 'we both companies' soooo didn't sit right with me! That's so much better.

Congrats and well done. Good luck.

If you ask me, the word "both" is wrong. You could say I don't think "either" of our companies (if you left out the word "mutually" later). You could also just leave it out entirely and say "I don't think our companies....

The word "mutually" already implies a reciprocal feeling on that score (or, at a minimum, that any happiness that may have been felt by one company was NOT reciprocated by the other).

Of course, it depends on just exactly what you are trying to say. For example: "Neither of our companies have been happy with the other" would basically say "We don't like each other."

Thank you so much again layman! This is another batch from the native speaker I told you about yesterday

Here's a little gratuitous advice for you, Jaqen: Don't listen to another word he says if you're trying to understand English. On the other hand, if you just want to show how wrong he is, and rub it in his face, well, that's up to you.

LOL Thanks!

I do not think that both companies have reached an understanding with each other.
I do not like to use 'don't'.

You can remove 'that'.

Why not? It is often more appropriate, especially in informal contexts.

Maybe he's a Geordie.