A false friend is selfish and worse than an enemy. He will not want to help you when you are poor or ill. This kind of friend should not be trusted at all. He is not a loyal friend because he will not stand by you when you are in need.
A true friend can influence you to become a good person. He will help you if are weak in knowledge and will care for your comforts, needs and happiness.
Be loyal to each other. Make as many friends as you can. Never speak ill of your friends or try to spoil their name by loose talk. False friends are also.