Help! Christmas gift for my wife (mystery 90's RNB song)

My wife has had a song stuck in her head for the last 30 years. We are simple folk and don't make a big deal of Christmas, gestures usually over big presents. I'd love to gift her this mystery song that has been plaguing her for most of her life. I don't have much to go on. Please help! It goes:

dah...dah...duh...dah...dah...dahhhhhh......dah...dah...duh...dah...dahhhhhh...dah

It was a relatively popular RnB pop song in the US from early 90s maybe late eighties. Slower jam. Edit: I believe it is a female artist and my crappy rendition above is from the beginning of the song.