Hm...if I liked someone, but was afraid of rejection, what would I do? Interesting question...
I think it all depends a lot on the situation. For example, depending if it was someone you know well, or a person you just met, that could make a difference. But for me personally, being the shy person I am, I think that I would probably feel around a little first and see if I can pick up any hints as to whether or not they liked you. Of course, that's just me personally.