You can disbelieve what Assange says if you don't believe him. Discounting what Assange says, explicitly, clearly and deliberately because Hannity is interviewing him is foolish. It was a friendly interview. So what.
Weird how I didn't mention any of these in my comment. The problem is that the interview is not designed to elicit credible testimony. It's designed to put on a show. Thus, I discount it heavily.
Not to mention the way the questions were worded allowed Assange to answer without answering. Did the Russian government directly give Assange that data? No, and that would be hilariously inept for Russia. The way Hannity phrases all his questions allows Assange to easily answer "no." Just a terrible interview.
This "interview" is why Hannity is not, and should not be considered, a journalist.