When teacher Jennifer Lim lost her wedding ring in a game of touch rugby at East Coast Park in 2008, she thought it was "impossible" to ever get it back.

But last month she did, thanks to the persistence of a full-time national serviceman who found it four years later at a bus stop in Eunos.

It is not known how the ring ended up there.

Mr Aliff Noor Hakim, 24, saw the name Collin Toh and the date "6 Sept 03" engraved inside the $400 platinum ring and set about searching for him on Facebook.

After finding Mr Toh's profile, which had a matching wedding date, he sent him a message but did not receive a reply. Mr Aliff sent several more messages over the next three years, until Mr Toh finally replied in June this year.

"Somehow, I missed his messages," Mr Toh, 37, a businessman, told The Sunday Times. "But Mr Aliff did a great deed to search for me to return the lost ring."

Ms Lim, 37, added: "I was really, really amazed to hear that someone contacted Collin about a ring. It has been seven years and the ring has such a dull colour. I thought it was impossible to be reunited with it.

"Since I lost it, I did not really dwell on it, but I did think about the ring recently. It's really a miracle."

Ms Lim lost the ring during a touch rugby game while making a pass, and the group stopped the game immediately to look for it.

She said: "We bought another pair of rings a year later, but I wore mine for only a few days as it didn't feel the same."

The couple met Mr Aliff last month to collect the ring, which he had kept in his grandmother's sewing kit. "I'm very happy the ring was finally reunited with its owner," Mr Aliff said.

"I'm not married, but I know how it must feel to lose something so precious, which was why I kept it.

"I wanted to find the owner. If I had left it at the bus stop, people might not see it as it is very small."

Mr Toh, who had proposed after a six-year courtship, said: "We felt that the rings with our partners' names would be very meaningful."

The couple, who got married in 2003, have a son, Caden, nine, and a daughter, Caren, eight.

While the ring is now too loose for her, Ms Lim is looking at how she can wear it again. She said: "It has sentimental value, being a proposal and wedding ring... For now, I'm keeping it at home."