When preacher preach about they talked to God and the Lord told them this or that. How would I know if they?

are telling the truth or not. I was listening to this pastor at church and she was saying that she tried to kill her self with pills three times and she did not work,. So she said she had a dream this person told he the lord said to cut it out. LOL my mother use to say to use when I was younger. Thy shell no lye and the other10 commandments what do you think about this . I can't remember exactly everything so this is to make a long story short. So what do you all think of this.