some people may never be trusted you do not have to learn to trust one who has lost your trust ,rather it is they, who must earn your trust by their actions ,from the first day and there-after you forgive them ,and allow them to be a part of your life. You didn't give us much to go on, but sometimes a parent will lie about something thinking they are preventing you from becoming hurt. They love you and want to protect you. What may seem as no reason to have a parent lie to you is a good reason for you to put yourself in your parent's shoes. What if you had a young child and there was something in the family (perhaps a mother or father leaving the family or the mother didn't marry your father and raised you herself and lied about it) is it so bad? If you can figure out you've been lied too, then you are old enough to be mature enough about it and sit down and communicate with your parent. No yelling, no drama, just listen! Life can be very complicated for both the young and adults. Don't judge so quickly. Give your parent the chance to explain themselves.