How can you tell if someone is lying to you?

Body language. Touching or covering the mouth or throat, for example.

With my ex-girlfriend, whenever she opened her mouth.

Realistically there is no universal sure-fire sign that someone is lying. All of the signs, behaviors, and indicators linked to lying are simply cues that might reveal whether a person is being forthright. So taking a more active approach to uncover lies can probably yield better results but most importantly just trust your instincts.

If they are a politician.

Looking down or to the side while talking, but looking up is a sign of trying to remember. But those are just clues, and not 100% guaranteed

The most dangerous liars are those who think they are telling truth. In the end liars are liars simply and they are disgusting people.

In the end liars are liars simply and they are disgusting people.

. . . but sometimes it is necessary. Some people cannot handle the truth. Omitting truth (not actually lying) is a good tactic too. What you don't know can't hurt you.

RoFL@ Tony Alderman !

When they call it "tatemae".

Simply put lying is one of the most common, habitual tactics used by a person with a disorder or disturbance of character. This type of person avoids taking responsibility for behavior while simultaneously attempting to manipulate or manage the impression of others. Most people do not respect liars, users or fakers.

You can't, if they're good at it. There are people with nervous habits who tend to give themselves away, but then again they might just be nervous.

Novenachama: "Simply put lying is one of the most common, habitual tactics used by a person with a disorder or disturbance of character. This type of person avoids taking responsibility for behavior while simultaneously attempting to manipulate or manage the impression of others."

There are varying degrees of what is acceptable when it comes to lies. If someone asks me how I'm doing in passing, I'm not going to say, "Well, my wife left me, my pet died, and I'm in shocking debt" if that's what's happening that day, because it's none of their business and because chances are they are going to regret asking, so I will "lie" and say, "I'm so-so" or, "Not bad", or something like that. If a tiny child asks where a child comes from and you say, "from your mom's tummy" or a story just to entertain them and/or to avoid the birds and the bees at the age of four, technically you're lying, but is it something that should be disrespected? Lying is lying, 'habitual lying' is something else.

I mean, are you telling me that Novenachama is your real name? :)

There is an old and tried method used in the UK, to tell if a politician is lying. If his mouth is moving.

Many of us have learned to differentiate between little white lies to spare people's feelings and downright dishonesty because as children we all lied. However my parents taught me the importance of honesty early and how to resolve situations so I didn't need to rely on lying and it ensured me to be honest most of the time.

They're posting on the Internet.

Novenachama: "Many of us have learned to differentiate between little white lies to spare people's feelings and downright dishonesty because as children we all lied."

You said "lying". Period. You did not later clarify between types of lies, which is what I did, and what you backtrack with in your second comment. It's good that you are honest, but again, lying is not always a bad thing and does not necessarily make you a dishonest person -- and hence you post with a handle.

When they bleed for days but doesn't die