Can people easily tell if you are being authentic? They may not be able to tell right away, but they will be looking for signs that your words and your actions are matching consistently. Basically, they want to see if you are being honest and transparent when you talk to them. There will only be trust when they see that those things are in alignment over time.
There are other ways that authenticity in a person is also measured. Do you show respect to others whether they are in the room or not? Are you gossiping about them with others? Do you do things behind their back because you think it is easier than confronting them when you disagree? These type of behaviors will eventually be visible to others and it creates doubt about whether they can trust you or not.
The best way to see if you are being authentic is to do a little self-evaluation and then ask yourself two questions. Evaluate how you are showing up in your interactions with others. Look at the words you are using and/or the actions you are taking. Question one is “would you want someone to say or do this to you?” Question two is “would you say or do this to someone in your family or a close friend?” It the answer is no to either of those questions, then you may want to reconsider how you are showing up and make some shifts if you want to be viewed as authentic.