Complex sentence: A goal of many Shinto rituals is to achieve a "pure" or "sincere" heart, "makoto", reflected in a "unity with things," or a "communion" with the kami spirit of the natural and social world.
Split into simpler sentences: A goal of many Shinto rituals is to achieve a pure heart in communion with kami. This sincere heart, "makoto", is reflected in a "unity with things," or a "communion" with the kami spirit of the natural and social world.