Katara's feelings towards Envy are incredibly complicated despite seeming so straight forward. When they first spoke she had no idea who he was or what he'd done, and they were at least acting civil. She sees something in Envy that she doesn't want to see though he probably doesn't realize it. Unfortunately Katara doesn't have the greatest history with letting her guard down around enemies, so needless to say she's wary.
✘ .//. Envy » Ieva