Yes, you can reapply if your Singapore Visit Visa is rejected. If your Singapore Visit Visa gets turned down, you can apply again. Make sure you know why it was denied and fix that in your next application. Often, visas are denied because of missing documents, not enough money, or an unclear reason for your visit. Wait to reapply until you have better documents, like current bank statements, a trip plan, or invitation letters. You don't have to wait a set amount of time before reapplying, but sending in the same application again probably won't work. If you need help, talk to a professional.