Hi Vahdyx!
Thanks for posting your question in the Apple Support Community! I understand you want to be able to let your guests use your iPad to send out an email but don't want them to see your personal contacts when they do so. I can certainly understand wanting to keep that information private and I'm happy to offer a suggestion.
Before making any changes, I recommend to make a backup of all your data to ensure that everything is safe. The steps I'm going to suggest shouldn't delete any data. You can find those steps here:
How to back up your iPhone, iPad, and iPod touch
Depending on how the contacts were added to the iPad, you may be able to turn them off for the day. If your contacts were synced using iCloud, all you would need to do is go to Settings > iCloud > Contacts and turn the toggle off. This will remove your iCloud contacts from the iPad but won't actually delete them. They'll still be safe in your iCloud account and you can verify that by going to the iCloud website. You would go back to Settings > iCloud > Contacts and turn it back on when you're ready to re-sync them.
If your contacts are being synced through an email account, you can go to Settings > Mail, Contacts, Calendars then select the account and turn the contacts option off. This should stop the contacts syncing from your device but shouldn't delete anything. They will still be available in your email account. You can then go back to that setting to enable those contacts at a later time. If they are synced with an exchange email account, you will want to contact your IT Administrator for help to stop syncing the contacts.
A last option that you have, if your contacts are not being synced from any accounts, would be to backup using the article above, then temporarily delete the contacts. Once your wedding is over, you can restore your backup using the article below.
Restore your iPhone, iPad, or iPod touch from a backup
Cheers and congrats on your wedding!