Believe Me
Meaning
Be assured; be certain.
Used other than figuratively or idiomatically: see believe, me.
Source: en.wiktionary.orgSynonyms
Examples
It may be imitative of the Harvard anthem "Fair Harvard," which is also sung to the tune of "Believe Me, if All Those Endearing Young Charms."
The best known of Kern's songs from this period is probably " They Didn't Believe Me ", which was a hit in the New York version of the Paul Rubens and Sidney Jones musical, The Girl from Utah (1914), for which Kern wrote five songs.