Can those fortune tellers outside believe it?

Not credible. If you really want to count divination, you might as well go to Taoist temple. Setting up a stall in the street or opening a storefront for divination is nothing more than a good memory, or practice makes perfect. Write down some things in photo albums and divination books, and ask you questions according to the date of birth, so as to get information that he thinks is useful and tell you what is in the book. Because you inadvertently revealed the answers to some of his questions, you will feel that his calculations are accurate, but in fact they are not. The fortune-telling of Taoist priests will not be so simple. They will help you calculate according to the change of gossip, the layout of the stars and the orientation of the five elements of Zhouyi. 100% is not necessarily effective, but it is much more reliable and accurate than that on the street. After all, it is professional. I hope my answer is helpful to you.