Sincerity has become one of the noblest attitudes that we expect our surroundings to have. It builds trust among friends, colleges, family, and even lovers. But sometimes sincerity might be hard to identify.
If I am not mistaken, there is a line in "How to Be a Stoic" by Massimo Pigliucci about sincerity.
"Sincerity is where you treat people without looking at them like a tool." You interact with people according to your purpose for interacting, without any hidden intention.
When I was in middle school, sometimes I lied to my parents to sneak into an internet caf to play online games. I remembered designing my actions with hidden intentions whenever I interacted with them. However, the more I lied, the more I learned that someone might easily lie to me too.
How can we know someone is lying? How can we know someone is not acting? How can we know that we are used as a tool for someone's purposes? The answer is that we don't. I think that's why, until this day, I'm not comfortable with direct compliments.
"Wow, you are so good at this.".
"You are the best person that I know."
"I'm proud of you."
Maybe, just maybe, it's all just spitted lies to get your affection for them. To make you someday payback for those rare compliments.
When I was entering college, I studied a few communication and body language tricks during my first year of taking responsibility as a leader for my friends. I adapt my communication style intentionally to every kind of situation and character. In simple terms, a manipulative person.
Slight touches, staring at the eyes, leg orientations, and tilting the head when listening. I learned to make connections with every single person I met. I don't care what they were saying; what I know is that I will just water them as much as they want so that someday I can pick them like flowers. On the surface, it looks like someone is just being a good friend and trying to show their interest in the topic, but actually it is all for a hidden intention. The more I learned it, the harder it became to trust someone.