未婚夫簽證 or 旅遊簽證哪一個是比較容易?

未婚夫簽證 or 旅遊簽證哪一個是比較容易?
I have a friend who is 33 years old. Her boy friend is a american. they met this May. He tries to let her come here for a short visit before they satrt to plan marriage. Just wonder 未婚夫簽證 or 旅遊簽證哪一個是比較容易?

Thanks.