is online business can provide you a stable income for your whole life ??

Yes, but it takes considerable time and effort of develop systems which work. The key is to notice what works and what doesn't. Cut off the things which don't work quickly. Don't keep making the same mistake repeatedly.

But if something works, then repeat it, over and over. Apply it in every possible way you can think of. Don't switch to anything else until you have figured out how to maximize the return on something that's working in every possible way.

It may sound obvious, but I bet not one in 100 Internet Marketers actually do this, and they're leaving money on the table.