No matter who you are, there's always someone in your life that you really want to come out to, but you already know that they're not going to make things easy for you. They will have trouble accepting and will take some reassurance. However, before you go to that person, make sure you have a support system. Your support system has to be a person that can accept your sexuality easily and will give you the backup you need before going on over to the person you want to come out to.
A lot of people don't realize that being surprised is a natural response to others finding out your sexuality. If a close friend or family member is surprised by your sexuality, it does necessarily mean that they're disappointed. You're breaking major news to them, and it'll take them a bit of time to accept the news. Give them the room to understand the situation and to let it sink in.
Personally, if you're asking how to come out as bi, the first important thing to note is that it's not necessary for you to come out. It is a huge burden off your chest when you come out to family friends; it's not essential. You can live comfortably with your sexuality hidden from your family and friends. You have to know that it's an option, not a compulsion.