Lyric discussion by SWLinPHX 

Cover art for Clair lyrics by Gilbert O'Sullivan

This was written for his manager's daughter who he used to babysit, as a gift to his parents, and hit it big in many nation, including the U.S. and U.K. There is a video of him playing with Clair at the time with the song playing on YouTube (sort of a makeshift music video from 1973).

Some of the lyrics were questionable with regard to a grown man being so in love with a little girl he was unrelated to. "In spite of our age difference", "each time I leave you I feel I could die", "to me you're more than a child". But it is, in the end, an innocuous tribute to a little girl who he is still friends with today (in her forties).

A gift to "her" parents I meant.

By the way, the correct lyric is, "I want to marry you; will you marry me, Uncle Ray?"

The singer's real name is Raymond O'Sullivan (he changed it as a play on the famous duo "Gilbert & Sullivan") and Clair used to call him Uncle Ray when he babysat.