Since a similar/related question was answered by /u/Commustar about a month ago, I'd recommend to read his (great) answer.

But to cut to the heart of your question:

For his part, Emperor Haile Selassie was cautious about being cast as a messianic figure, and in 1967 he publicly stated that he was merely a man, was mortal, and people should not believe he is an emanation from god.

But like I wrote at the start, I really recommend to read the entire post by /u/Commustar.

Here's a clip of when the Emperor came to visit Jamaica.

Commemoration of his arrival on this visit is celebrated by Rastafarians still called Grounation Day. He never actually denied his supposed 'divinity' which is more about his respect for people having beliefs than him actually acknowledging it. He did try and use the 'celebrity' to convert the Rastas to the Ethiopian Orthodox Church, but then on the other hand gave Ethiopian land to the Rastafarian community. Hard to see a clear motive/opinion besides confusion and calmness.

Why did they think he was a god?