Verum shi, sentence-final de and the emphatic effects in Mandarin

•Shi and de share the same core semantics of being verum operators.•They indicate the speaker’s certainty towards updating the prejacent into the CG.•They differ in discourse licensing conditions.•Shi is defined iff there is a salient or hinted p in the previous discourse.•De is defined if the QUD is a yes–no question about p.