You will get more than one interpretation regarding this passage. I will give you one, which is accurate, but which may not be the choice of another person. Note that varying uses of English will be part of the reason for the differing replies you may receive. One of these differences is the tendency, especially in North America, to use the plural where the singular should, in fact, be used. This seems to stem from a desire to avoid using the masculine to represent the feminine. Those who speak gender based languages such as French or German (to cite two) find this a rather unusual, and at times a difficult to follow, approach.
Every person in this life has personal traits, and an individual personality. These things help to make him different from other people. Daily life plays a major role in establishing these traits. Everyone expresses his personality through his interactions with other people.
Many adjectives can be used to describe these traits. These include: shy, stubborn, ambitious, talkative and hard-working, to mention just a few.
To sum up: One who does not know another individual personally will always base his opinion of a given person upon the personality traits which are publicly visible at the time when first acquaintance is made. As such, an individual should always be careful to present the best possible public persona.
Note that this is an interpretation of your wording, and not a precise correction. I hope it will help you to find the wording you need for your written material.
Student or Learner