In Internet slang, a troll is a person who sows discord on the Internet by starting quarrels or upsetting people, by posting inflammatory, extraneous, or off-topic messages in an online community (such as a newsgroup, forum, chat room, or blog) with the intent of provoking readers into an emotional response or of otherwise disrupting normal, on-topic discussion, often for the troll’s amusement. (Wikipedia)
So it is irrelevant if the troll believes what he writes or not.