Luckily there were always painters with sufficient confidence or cheek to pay no attention to the rules, whether old or new. (theguardian.com)
It took him at least half a year of tweaking before he felt sufficient confidence in his data. (sciencemag.org)
Solution: If you honestly believe you're going to lose business by putting your family first, you lack sufficient confidence in your professional ability to be a top salesperson. (realtormag.realtor.org)