Complex sentence: Sunnis believe that the Sahaba were generally upright and truthful, although not infallible, and most Sunnis accept them in chains of narrations (isnad) unless they were proven to be liars or opposed to Prophet Muhammed.
Split into simpler sentences: Sunnis believe that the Sahaba were generally upright and truthful, although not infallible. Most Sunnis accept them in chains of narrations (isnad) unless they were proven to be liars or opposed to Prophet Muhammed.