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.

We're GRATEFUL to have good, strong men
like you protecting us.
Game of Thrones Season 1, Episode 2

I'm GRATEFUL to all of you.
Game of Thrones Season 7, Episode 2

Grateful for your late father's
courageous support of his claim,
Game of Thrones Season 5, Episode 4

Be GRATEFUL I'm still in the room.
The Big Bang Theory Season 10, Episode 4

We'd be most GRATEFUL for any support
you could provide the queen.
Game of Thrones Season 6, Episode 5