Don't worry, my use of a particular psalm would only be used in certain circumstances.
I understand your meaning, that find what you really are is difficult because most what you hear is opinions, and mere compliments than honest assessment of you. I will say that in Paul Washer's words when quoting one of his mentor
"Paul, your best friend is the one who tells you the most truths"
For certain facts that's not always the case. A wife would ask her husband if she's fat, a person with physical (a) disability(ies) asked his best friend if girls would find him attractive, and grieving parents asked their son's best friend and comrade how their son really died in combat.
Certain questions in relation to subjects can prove too much.
But in terms of character, a true friend will tell him/her their virtue and flaws. If your friend often comments you on your sincerity, you can take it as an isolated opinion. Two people, maybe, but if three or more states the same, then there's truth to it. Same thing if you are told if you're stubborn, difficult to be with, stuck-up, arrogant, cold, harsh, hard around the edges, etc.
Good friends are ready to compliment, but best friends tells you the positives and give negatives in a form of constructive criticisms to you.