In fact vs as a matter of fact They mean the same , as in saying something as a follow up to what you have said earlier as to correct it . ( as in REALITY, actually ) You said that I have not been helping him when ,in fact/as a matter of fact , I have been doing that without them knowing . But , "as a matter of fact" is normally used as a response to a statement which you want to clarify because you have different OPINION on it ,and you wish to add to that by speaking . 1) >I saw you going out with him ; I thought you hated him. > As a matter of fact , I still do . = In fact , I still do ( interchangeable from different perspective) )In fact = as in reality Matter of fact = to offer a different opinion . I still love her , as a matter of fact ( offering your differentt opinion when others say you dont) In fact , I still love her ( your are just stating the reality , not so much as to correct their wrong opinion of the relationship)

They're the same. You could almost always use on where you would use the other. I can't think of any time you would not be able to use one instead of the other. "As a matter of fact, Los Angeles is in California." "In fact, Los Angeles is in California." They're usually used to cite something as part of a debate.