@Manusia hello, are u Indonesian?
Being authentic is, from my personal experience is being free from ego or your ruminating minds, u do things because simply u just want to do it, not because your mind told u to do it. Not because i should do it, but i do it, there's even no mind thinking ure doing, just doing.
I know it sounds weird, but if u observe ur ruminating mind, it full of judgement and fear. Fear of being judged, or judging wether what ure doing is right or wrong. If ure doing things with all of that baggage, ure not being authentic. Being authentic is simply dropping all of that and just go with the flow. Wu wei