I have not always acted and spoken in a truthful manner. I have been very hesitant to speak and act truthfully in case it made you reject me.
A person's actions and speech are a way to tell if a person knows the truth. If the actions and speech do not reflect the truth, chances are that the individual does not know the truth.
If you are unable to act and speak in a way that represents the truth there is a fair chance that you do not know the truth. Of yourself you cannot know the truth otherwise you already would have.
1 John 2:4 Whoever says, “I know him,” but does not do what he commands is a liar, and the truth is not in that person.
He Who Is Truth would help you know Who He Is, so much so, that you would be able to act and speak in a way that represents the truth
1 John 2:8 Yet I am writing you a new command; its truth is seen in him and in you, because the darkness is passing and the true light is already shining.
1 John 2:20 But you have an anointing from the Holy One, and all of you know the truth.
1 John 2:21 I do not write to you because you do not know the truth, but because you do know it and because no lie comes from the truth.
1 John 3:18 Dear children, let us not love with words or speech but with actions and in truth.