confirmatory

adj

1. Serving to confirm something.

   “I replied, as I usually did whenever I had a chance, that nobody had ever loved anybody else as I loved Dora. Traddles came to my assistance with a confirmatory murmur.”

   “"Do you come to me, Master-at-arms, with so foggy a tale? As to Budd, cite me an act or spoken word of his confirmatory of what you in general charge against him. […]"”