Currently, I cannot find a way to send messages that does not end up in the hidden "Other" folder. The only way is that you become friends and then send the message. I have tried to send a friend request and then send the message but it still ends up in the Other folder (unless if I send the message after the friend request has been accepted). If you do not know already, users do not receive a new message notification if the message ends up in the Other folder. The only way that they will discover it is by clicking on their messages and then clicking on the Other sub-folder. There must be some type of workaround for this very annoying issue. If you have a solution, please share.