Unsure

A gentleman in front of me on a motorcycle was listening to this song, I felt it was not appropriate to chase him down, but now after several hours of searching I'm thinking maybe I should have...anyway, I believe it is a male artist and the only line in the song I was able to hear was: "I gotta tell you something, might make you change your mind". It could have been I need to tell you something or I have to tell you something, but no matter how I search it, I'm unable to find anything. Please help!

"I'll show you something to make you change your mind"?

"Streets Of London" by Ralph McTell
https://www.youtube.com/watch?v=YKu4DaPi-qY

I don't believe this is the song, I've listened to it and several covers, unless I just haven't found the person doing the cover since I know it's not the original artist that I heard. I feel like this one might haunt me for a while!