Confucius said: “Without anticipating deception or suspecting bad faith, but still to be able to sense them beforehand, is that not what wisdom is?”
Useful advice: always be ready to the see the best in people, but also be prepared for the worst.
The character 賢 (xián) literally means both able and virtuous. In this context, wisdom seems be the most appropriate translation. Perceptiveness would be a good alternative.