Even though Waikiki is one of the busiest places on all of the islands, you’ll still find there is a chance to pause and enjoy the sunset together. In fact, most everyone pauses to watch the sunset as the beach and city goers all stop to be grateful for the day.
There isn’t a bad spot to watch from, but to get a little away from the crowds you can walk just a little to the east or the west along the beach. I prefer going east toward Diamond Head and being down near Kapi’olani Park.

If the sky is clear, you’ll be able to see the green flash just as the sun disappears below the horizon.
Take it all in and enjoy, you’re on vacation with the one you love.
Oh, and don’t be in any rush to get up and leave after the sun goes down. Depending on the cloud, there could be some very beautiful colors to be seen in the next 10-20 mins. Don’t be in any rush, even if the people around you start to walk away. Enjoy this time together.