Common Mistakes : Confident

.BAD: I feel quite confident with my English
.GOOD: I feel quite confident about my English

: confident about sth
.The more familiar you are with the machine, the more confident you will be about using it

.BAD: I began to feel more confident of myself
.GOOD: I began to feel more self-confident

: If you have confidence in your own abilities, you feel self-confident
.Even as a child he was surprisingly self-confident and didn’t mind being left with strangers