While generally, yes, a request for your passport is a great sign, it does not 100% mean that you are approved and will get your visa. You don't say which office you've applied through. Some visa offices will request a passport early in the process, some later. The letter that you get with your passport request should say something along the line of a 'request for your passport is not a guarantee that a visa will be issued'. For instance my husband had a passport request, we submitted his passport and then it was returned with a request for another police clearance report. Once that was submitted, they requested his passport again and then got his visa in a few weeks. Good luck!