True friends aren't phony with you. They show you who they really are. They're honest with you when it matters most. They never try to deceive you to make themselves seem stronger, more successful, or better than they really are. A true friend goes beyond the surface, any true friendship requires some level of vulnerability. When a friend opens up to you and shares their struggles and disappointments, it is a testament of the trust and value they place in you. Having a friend that shows you that they trust you with their authentic self is a good indicator that you can do the same with them.
A true friend is not only honest about themselves, but they are also honest about you. They are able to have difficult conversations in telling you things that sometimes you may not be eager to hear. The key is that they do it in love and with grace. They don't tear you don't tear you down but rather a true friend will hold you to a standard they know your character is worry of.