Is this search engine reliable

No, defintaly not. If the question is asking about WikiAnswers, it is not a search engine. It is a Q & A site, and it is only as reliable as its contributors. We have all kinds, as evidenced by the previous answer, written by the same individual who asked the question. A search engine finds sources of information so that you can answer your own questions. This site gives you the answer, which is not guaranteed to be reliable. By the way, the Word is spelled "definitely."