Arabic text
عن ابن عمر رضي الله عنهما قال: ما سمعت عمر رضي الله عنه يقول لشيء قَطُّ: إني لأظنه كذا، إلا كان كما يظن.
Translation
Ibn ‘Umar (may Allah be pleased with him) reported: Never have I heard ‘Umar saying about something: "I think it to be so-and-so", but it proved to be as he had thought.
Explanation
The Companions used to see ‘Umar ibn al-Khattāb (may Allah be pleased with him) judging matters that were not clear or understandable to them. Then, afterwards, after these matters became clear, they would find out that ‘Umar's judgment regarding them was correct and in accordance with the way those matters unfolded in reality.
Source: HadeethEnc.com