If you want to use bursts without flash, depending on ambient light only, you will need a very high ISO, which may result in noisy images. Be sure to turn on the Noise Reduction Feature. From your description I am reading you want to get the entire arc of the flower toss, hence the burst. These images may well look like crapola due to the noise. Be sure to turn on Noise Reduction. Your settings will depend on the ambient light levels, there is no way I can advise you, except to say keep the shutter speed as high as you can to avoid shake and movement blur. I assume you will then composite the images to show the entire arc. Lots of work there.
An alternative is that you use a flash. If you time it right ( use second curtain setting) you use a longer shutter speed, and the flash goes off when the flowers are at the top of the arc. What you get is the flowers blurring on the way up to the top of the arc, and down into the crowd of women fighting over the flowers. The flowers would be frozen by the flash at the top of the arc. This requires perfect timing on your part. Hopefully the bride will be frozen in a pleasing position when the flash goes off. Ask her to look at you and freeze as she tosses the flowers. Brace yourself (or use a tripod) to avoid camera shake.
Or you stay safe: Use the flash with 1/250 shutter speed, watch her carefully, and shoot when you see her let go of the flowers. Everything will be frozen, but the bride will be in focus (extremely important) the flowers will be on the way up and the shot will be clean. Depending on how fast the flash recharges you may be able to get two shots. Set to burst but shoot as if you are only doing the one shot.
If you have time, get some flowers and a friend to help and PRACTICE. I'd make time for that.