The duet by Nat and Natalie Cole is a beautiful song, but it will be difficult to dance to. It's a foxtrot but it is 88 bpm. For slow foxtrot that is excruciatingly slow, and unless you are very very good, you will probably find it too difficult. I will go even further and say that even the professionals will find this very difficult. The recommended minimum speed for slow foxtrot is 112 bpm. You could do bronze American foxtrot but that will feel even slower, however it will be doable in bronze because it doesn't have that large rise and fall, but it will feel almost like you are standing still.
Keeping the time will also be difficult for someone without a lot of experience because the music goes to something very soft while they are singing and there are no strong beats to sync to.
I guess you could choreograph a bolero to this. It is bolero speed. I would rather attempt that, than a slow foxtrot. However bolero is not a beginner dance.
I also used this song at my wedding, but I used it as the second song where the bride and groom get to dance with the parents. This was to be a slow dance, because some of them didn't really know how to dance and everyone can look good with a slow dance. It worked great for this. If your first dance is to be a slow dance, this would be a good choice for a song.