Sentence:  Unsurprisingly for a man who went into mourning for three years after the death in 1994 of his own father, the legendary leader Kim Il-sung, and who in the first 30 years of his political career made no public statements, even to his own people, Kim's career is riddled with claims, counter claims, speculation, and contradiction. There are few <WSD>hard</WSD> facts about his birth and early years. 
Meaning of the word marked with <WSD> tags:  Unquestionable.