路遥知马力，日久见人心。【英】

distance tests the strength of a horse; and time reveals the true character of a person.

译文来源

http://english.gov.cn/premier/speeches/2016/09/09/content_281475437552250.htm

例句

1. 中国人常说：路遥知马力，日久见人心。——《李克强在第19次中国－东盟（10+1）领导人会议暨中国－东盟建立对话关系25周年纪念峰会上的讲话》

1. As we say in China, distance tests the strength of a horse, and time reveals the true character of a person. —Quoted from Remarks at the 19th China-ASEAN Summit to Commemorate the 25th Anniversary of China-ASEAN Dialogue Relations