simpleman, ai mai nia means you have a choice to lie or not to lie. if one is determined to lie, the lie can be so well designed and executed that not a trace of untruth can be detected.
But lying, other than will, takes skill. Some people lie because they are good at it. Some people don't lie because they can't live with having told a lie. Some people want to lie but can't because they get exposed the very next minute.
For me, most of the time I choose not to lie. Even in situations where everybody lies to get that hot job, I naively tell the truth and reveal my lack of confidence. *sigh* What's worse, I can't lie very well. My conscience will keep bugging me and given my super kiasi character, I do not want to be faced with the consequences when I get exposed.