“sanantano” in the above verse differs from “santana,” which is not a Pali word.
“santanano” can be interpreted as “leading to the end of “san” (i.e., “san” + “anta” where “anta” means “end”). Here “sanantano” means “end of ‘san’ is accomplished with“
Thus, the verse can be translated as follows:
“Hatred is never appeased by hatred
It is appeased only by loving-kindness
Non-hatred leads to the end of “san” (“san” + anti” rhymes as “sammanti“)
That Dhamma (Buddha Dhamma with non-hatred or loving-kindness) accomplishes the end of ‘san’“
To attain the ability to generate genuine and automatic “non-hatred,” one must understand and follow the “anicca nature” of this world. Mere adherence to “non-violence” as a “sila” cannot achieve genuine and permanent “non-hatred.” In other words, only the “Ariyakānta sila” of a Sotapanna Anugami or above can have the basis of that mindset.