I think when people say or write, “To be honest” they are about to tell you something very direct, without sugar coating it. I’ve noticed on this site, that sometimes an OP will ask a question, then they will receive 1 to 100 really good, helpful answers that may be similar.
Most people on Fluther at least attempt to be polite in the first place, but after certain OP’s just don’t seem to be getting the message, they are likely to get an answer that starts with “To be honest” followed by the same advice that the other 100 people gave, but in a much more blunt manner.
The first answer might be something like: “I really think you should evaluate the relationship that you have with this guy. Something is clearly wrong.”
The 101st answer might be something like: “To be honest, you need to break up with this guy now! He told you that he was sleeping with your best friend. Unless you enjoy being treated like crap, then you need to break up with him.”
The term “actually” is often put into spoken responses or written responses after someone has misinterpreted part or all of what the speaker was saying. Such as: “Actually, Bob, what I meant was that your wife is cheating on you, not just that she spends a lot of time out of the house at night.”