Because fortune-telling and Chinese medicine both come from the "Five Elements Theory" and an ancestor of Zhouyi, since Chinese medicine can cure diseases, birth can also give people a good life. From the eight-character theory, it can be seen that what diseases people will get under what fortune is actually similar to the theory of Chinese medicine.
Therefore, the eight-character marriage is accurate, but you must meet a really clever master. Just as Chinese medicine can cure diseases, for one thing, if you meet a quack or a liar, you may also kill the patient.