sich bewähren means to prove one‘s worth or value, to be reliable, to have worked. From Middle High German meaning to turn out to be true, right, correct.
In Germany there is no higher testament to quality than something which has proven itself over time. Das hat sich bewährt, that has proven itself, is very persuasive to German ears. Over generations, decades, even centuries. Solid, known, established, predictable, tested.
In German literature and movies, the harking back to family, tradition, home region is a constant theme. The ideal, idyllic world is to be protected against the corrupting forces of modernity.
German companies, time and again, advertise their solidity, quality, reliability by stating their longevity and tradition: Established 1885. Above the entrance doors of German Fachwerkäuser – half-timbered houses traditional in the Middle Ages, also called gingerbread houses – one can read Erbaut 1375.