I understand how afraid you are of being rejected. Don't think that you're alone. Nobody likes to be rejected and every one feels afraid to stick his/her neck out and get hurt.
One of the things you need to remember is that just because you believe something doesn't make it true. For example, you believe that your ego will be irreparably bruised if you are told no. That's what you think, but I promise you that this isn't true.
Think about all the people in the world who have risked themselves having tried again and again, and failed again and again. It is said that the only people who fail are those who don't try. If you tell yourself that no matter what the outcome, yes or no, you are a success for having had the courage to take a risk, you will be giving your ego a pat on the back and this will compensate for any sting that you may feel in response to being told no.
Remember all the successful people in life have tried and failed a lot. I believe that William Faulkner tried to get his writing published and was rejected 638 times before he finally found a publisher. He obviously didn't focus on failure. With each no, he kept on going, knowing that each failure brought him that much closer to success.
People who succeed in love and in work, brush themselves off and keep on going. You can do the same. Also, keep in mind that you aren't going to be taking as big a risk as you think. You won't declare your undying love in a first conversation. Instead, you will start small and let the relationship evolve naturally.
It is said that women are the ones who actually make the first move by giving green lights to men, meaning that it is women who let men let men know in words and body language that they are interested.
Then and only then do men make their. If you wait to ask a girl out until you have received enough green lights, you are reducing your risk of rejection down to nearly zero!
All you need to do is start a conversation. Ask interested questions, smile, and tell her what you like about what she says or does. Then watch like a hawk for her green lights. When you see them, make your move and, I promise, you won't be hurt or disappointed.
Let me know how you do.