The 25-year-old singer said that he first approached Minaj online over the summer, but she didn't respond to his suggestion that they go on a date.
"We had a thing going on Twitter for a while," Williams told We Love Pop magazine
"She came over for the V Festival and we got chatting and I said I'd love to take her out and we left it there.
"She hasn't got back to me. So I'm still looking for love. Any nice girls out there? Hit me up!"
Williams also revealed that his newly-married bandmate Marvin Humes is fond of playing pranks on him.
"Marvin is more of a prankster than people realise," he said. "He'll set my phone alarm for 3am, then place it next to my head on the tour bus.
"When it goes off, everybody moans at me, and I'm like 'I didn't set it! I didn't set it!'"
JLS's new single 'Hottest Girl in the World' was released in the UK today. Their fourth studio album, Evolution, is due to follow on November 5.
Watch the video for 'Hottest Girl in the World' below: