Being truthful is the uttermost important things you should adopt in your daily life. Truth can reduce the stress and tension from your life. The person who speaks truth more often is always happy and relaxed.
According to Meena Om vision on truthful, she says, "truthful means to be one on all the three planes – Mansa, Vacha, Karmana – thought, speech and actions, and also negate all artificial behaviour, everything that is hypocritical." 
"When we come into this state, we are able to see the truth of others, then realize everyone has their own truth. They may not be able to realize this, but our endeavour is to realize our truth by being on the path of truth."

She added, "When we are on the path of truth, we get various reactions from people. These reactions propel us towards knowing the truth of our own individuality. Then we can work on yourself with more clarity. This is the beauty of truth. If we don’t walk on the path of Truth or are in hypocrisy, then we won’t be able to assess ourselves.
If we keep on getting affected by others – our energy gets consumed outwardly – which could have been used for realizing our true self.
So our endeavour should be to stay fixed in our truth. This is the only way to evolve. Realizing your true-self is the right step towards realizing the highest truth, and merging of these is real yog -- that makes one ONE with Supreme being.."