"How Can I Be Sure" is a popular song written by Felix Cavaliere and Eddie Brigati, and originally recorded by the Young Rascals for their 1967 album Groovin' with a single release in August 1967 affording the group their fourth Top 10 hit.

"How Can I Be Sure" reached #4 on the Hot 100 in Billboard in October 1967, ranking as the most successful (Young) Rascals' hit featuring a lead vocal by Eddie Brigati.

The single's B-side, "I'm So Happy Now" (also included on the Groovin' album), was written and sung by Rascals guitarist Gene Cornish.

Of a rock-oriented band such as the (Young) Rascals introducing a traditional pop-style song such as "How Can I Be Sure" Cavaliere has stated: "The only reason we were brave enough to do that was [that] the Beatles did 'Michelle' and 'Yesterday'."

"Spooky" is a cover of the Classics IV hit and was recorded in January 1968 but left unused for almost three years until it featured as the B-side to this single.