What is a true friend? It can be someone who does exciting activities with others. It can be someone who hangs with you at the bar and drink some beer. It's someone who will stick by your side even when others don't respect you or even stand up for you against that nasty ol' bully. It can be those who always tell the truth, whether they like it or not, which is this trope.

What is meant by true friends telling the truth? Well, when moral argument falls into deaf ears, this friend isn't someone who isn't always going to suck up to The Hero. If the hero has flaws (especially a moral flaw), his friend will point it out with full-on bluntness, making sure that the hero improves his behavior. If the hero is falling out of line, his friend will verbally chastise him, making sure the hero goes to the right direction. He may be someone who doesn't share the hero's interests or opinions, and would inform him about this, although they wouldn't mind a bit. Despite his honesty, this doesn't mean they can't be friends. This friend truly cares for the hero and wants the absolute best for him.

The hero's response to his friend can vary. He may take heed to his hurtful, yet helpful advice and becomes grateful for having a friend like him, although sometimes his gratitude may not be easy, and he may respect his personal opinions and interests. But if he doesn't appreciate his honesty, this will create fierce tension between the two and they may have their friendship to self-destruct.

There are two moral lessons regarding this trope. One, if a friend tells you something you don't like, then that means he/she is your real friend. Or two, friends should always be honest with each other no matter what.

The polar opposite of False Friend who happens to be a character's enemy pretending to be his friend. The friendship variant of Honest Advisor. Compare Vitriolic Best Buds for friends telling uncomfortable truths out of disdain for each other while still being friends. Compare Big Brother Mentor.

Examples:

Anime & Manga

• Despite her icy disposition Rei Ayanami of Neon Genesis Evangelion often shows no hesitation to call out Shinji and Asuka whenever necessary, and even went as far to slap Shinji for smack-talking his father.

Film

• From Adam, Harlan who is Adam's family's old driver is the closest thing of a friend to him, but he often deals with him with through harsh truths if he wants to improve his flaws and stern rebukes if he's out of line.

Live-Action TV

• In the Babylon 5 episode "Soul Mates", when Londo gets dispensation from the Emperor to divorce two of his three wives (he must stay married to one of them), he chooses to keep Timov--the only one who doesn't flatter Londo but will tell him exactly what she thinks of him (quite unflatteringly). Londo says of his decision, "with you, I'll always know where I stand." (And before this decision, she shows she does really care about him when she donates her blood to save him when he's poisoned by another of his wives--even when his death would eliminate risk of her being disinherited--but tells Dr. Franklin not to tell Londo of this good deed.

Religion

• The Bible seem to be an advocator of this trope. As quoted above, Proverbs 27:6 assures us that a loyal friend who tells uncomfortable truths to others, which represents the wounds, is a lot better than the enemies' pleasant lies, which represents the kisses. This also makes sense considering that God is not only the creator of the world, but is a friend to His people in fellowship with Him; for He brings uncomfortable truths to His people in a way to keep us away from the dangers of sin.