I am planning to start a business but i am worried that i will not succeed. May i know how long it usually takes before the business become profitable?

Talk to some people in the industry. Calculate your business expenses (everything from set-up to transport to advertising) and give it a 10% buffer. Assuming that you have NO revenue at all for 18 months, do you have enough money to sustain the business AND to survive? That should be what you aim for. That's what I did when I started mine.

Go in and trust the process. thats how all good business come out.