The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

and wish to reestablish
the MUTUAL benefits that stem
The Big Bang Theory Season 5, Episode 15

You'll be pleased to know our MUTUAL friend
Game of Thrones Season 2, Episode 3

in MUTUAL admiration and respect.
Game of Thrones Season 1, Episode 10

And from what I saw,
the feeling was MUTUAL.
The Big Bang Theory Season 5, Episode 12

So, what, am I not tying up loose
ends for our MUTUAL benefit?
Breaking Bad Season 5, Episode 8