Elon Musk left his home back in South Africa risked everything he had,went to Canada and subsequently come to the US . He dropped out of Stanford and started his company(which he later sold for millions of dollars). What made him take these risks?

Again you guessed it right, it's confidence !

We live in a world where risk (for most of the part) is directly proportional to reward, to get the latter you must also take the former for which confidence is a must !