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.

A morally ambiguous CONFIDENCE man
who smokes, has lung cancer...
The Big Bang Theory Season 2, Episode 20

Confidence is key in these situations.
The Big Bang Theory Season 8, Episode 19

your CONFIDENCE and your trust,
Game of Thrones Season 3, Episode 4

I was filled with CONFIDENCE.
The Big Bang Theory Season 11, Episode 10

I hope we might speak in CONFIDENCE.
Game of Thrones Season 3, Episode 4