a safe bet
1. Something that is certain to occur. Based on his grades, it's a pretty safe bet that Harry won't be able to graduate on time.
2. A person or thing that is certain to be good or successful. The department felt that she was a safe bet for the account manager position.
a safe beta certainty.
A safe bet originally referred to a horse that was confidently expected to win a race.
2002 Observer It is a safe bet that as the Western world gets fatter, the people on its television screens will continue to get thinner.