证实(zhèng shí) - to confirm, to verify in Mandarin

证实 (zhèng shí) means to establish that something claimed is in fact true. It belongs to reports, rumours, findings and diagnoses, which is why you meet it most in news writing and in anything with a whiff of investigation about it.

It is comfortable in the passive: 消息得到证实, the news has been confirmed. The negative 未经证实 (unconfirmed) is a fixed phrase worth learning whole.

The trap is that English confirm does two jobs Mandarin splits. 证实 confirms that a claim is true; 确认 confirms an arrangement, a booking or a detail you already expect. Ringing a restaurant to confirm your table is 确认, and 证实 there would sound as though you suspected the restaurant of lying. 证明 is the third neighbour: it means to prove, with the emphasis on the demonstration rather than the verdict.