Move bookmarks BACK to the Mac

During a resent cleanup of my Mac, I forgot to save/backup 4 years of bookmarks.

Sometimes life (and Apple) gives a second chance.

The bookmarks are still in the iPhone.

I would like to get them back to the Mac.

In iTunes/iPhone/Info/Other I can see a selection Sync Safari bookmarks

Very nice, but I haven't checked this option yet, because I want to be absolutely sure that the bookmarks goes from the iPhone back to the Mac.

I can't really afford to loose all those bookmarks (again).

How can I get my bookmarks back into the Mac Safari?

Gear involved is MBP Snow Leopard w. iTunes 10.7 (21) and iPhone 3G with 4.2.1 (8C148)

Thanks...