Q: if i restore my iphone 5 will it delete my voicemail greeting ?

Are you restoring from a backup, or restoring as a new device. I almost certain if you restore from a backup, it should be alright, as I have never had to re-record mine. Come to think of it, I have restored my device as new before and still not had to re-record my greeting. I believe the greeting is kept on the carrier's voicemail server, since voicemail is a carrier function.

To be sure, you might want to call the carrier and ask them.

No. the greeting is on the carrier's server, so restoring the phone will not affect it.

That is what I thought.