Let's just look at a couple of famous examples. J.K. Rowling was turned down by 12 publishers before getting a, "Yes," for her book, Harry Potter. James Dyson had over 5,000 failed attempts at creating his famous vacuum cleaner and was turned down by countless retailers before receiving a single, "Yes." Just imagine if they had turned back and given up after the first, "No."
The same principle applies to you. You need to be prepared to hear lots and lots of, "Nos," before you can hope to receive a, "Yes." When someone tells you, "No," don't look at it as a, "No," look at it as a, "Not yet."