Yani score of 0 is not good, if that is what you mean. Yoni is basically the Sexual compatibility of the couple. A mismatch will lead to unsatisfied marital life on the sexual part, which in not good in a relationship. You need to check if Mars and Venus is strong in both charts. You also need to check if there is no major affliction on the 12th house and 12th lord, as 12th house is for bed pleasures. Marriage should be considered only after that.