Dealing with a chronic liar
Catching someone in a big lie won't prevent them from lying again.
To stop lying, they'd have to develop integrity and confidence. Catching them humiliates them which lowers their confidence because it makes them feel stupid and inferior.
When you realize you're dealing with a chronic liar, know that it has nothing to do with you and you can't fix it, but you have to distance yourself to the point where the lies can't hurt you anymore.
If they realize there's no benefit to lying but it only pushes people away, it may eventually give them an incentive to stop.
But that's a big if and you don't want to hold your breath waiting on it.
You do need to use discernment. You don't have to go full no contact in all cases.
With a friend, you may just be totally honest with them and tell them that you really can't trust them anymore but you really like them. Some good people may have had past trauma and use lies as a deliberate smokescreen to keep a distance from people they don't know well.
As for a spouse or best friend...no...you really can't have a chronic liar as it will drive you mad and you'll always have anxiety when you need to rely on their word. It's damaging to say the least. Let go with love.
Have you had your trust broken and aren't sure how to gauge if someone is being truthful with you or not? Learn how to trust your discernment better with the help of Doe's Books: