信而有征 Credible and well-documented
Explanation
指说话或做事确实可靠，有充分的证据。
Refers to words or actions that are indeed reliable and have sufficient evidence.
Origin Story
战国时期，魏国大臣魏文侯十分重视人才，他常常微服私访，寻找有才能的人。有一次，他来到一个偏僻的小村庄，发现一位老农正在田间辛勤劳作。老农虽然衣衫褴褛，但却精神矍铄，谈吐不凡。魏文侯与他攀谈起来，发现老农对时事、农桑都有独到的见解，而且言之有物，信而有征。魏文侯深感此人乃不可多得之才，便将其带回魏国，委以重任。这位老农果然不负众望，为魏国的发展做出了巨大的贡献，他的事迹也成为了后世传颂的佳话。
During the Warring States period, Wei Wenhou, a minister of the Wei state, placed great importance on talent. He often made incognito visits to seek out capable individuals. On one occasion, he arrived at a remote village and discovered an old farmer diligently working in the fields. Though clad in rags, the farmer possessed a vibrant spirit and remarkable eloquence. Engaging in conversation with him, Wei Wenhou found the farmer possessed unique insights into current affairs and agriculture, his words credible and supported by evidence. Deeply impressed by this rare talent, Wei Wenhou brought him back to the Wei state and entrusted him with important responsibilities. The farmer, indeed, lived up to expectations and made significant contributions to the Wei state's development. His story became a legend passed down through generations.
Usage
多用于书面语，形容说话或做事有根据、可靠。
Mostly used in written language to describe that something is well-founded and reliable.
Examples
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他的说法信而有征，不容置疑。
tade shuofa xin'eryouzheng,burongzhiyi.
His statement is credible and well-documented.
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这份报告信而有征，数据翔实。
zhefen baogao xin'eryouzheng,shuju xiangshi
This report is reliable and based on solid data.