was vriska honestly sorry when she apologized to aradia for killing her?

In my opinion, no.  She was just trying to redeem herself, no one really liked her at the time and she wanted to play the hero.  She had Equ build Aradiabot, not for the reaction of “Yay Araida has a physical form again!” but hoping for the reaction “Wow look what Vriska did, she’s amazing”