Khanti is to get to some kind of “relaxation” or “calming down.”
– When one sees how the samsaric suffering arises via Anuloma (forward) Paticca Samuppada process, one gets to Anuloma Khanti.
– That is a “cooling down” reached when one gets close to Nibbana by realizing the perils of cultivating sankhara “in hopes of enjoying worldly pleasures.”
When one also realizes that such suffering can be overcome by the Patiloma (backward) Paticca Samuppada process, one can see how that “cooling down” can be attained. That basically completes the two requirements to start pursuing the Noble Path.
– “Sammattaniyāma” may come from “sammā” + “atta” + “niyama” where sammā is to “remove san“, “atta” is “refuge”/”ultimate truth”, and “niyama” is a “law” or “principle.”