[Wolfram Mathematica][1], 34 bytes
=

    Tr[1^z]∣Tr[z=ToCharacterCode@#]&

Takes input as string, e.g.:

    Tr[1^z]∣Tr[z=ToCharacterCode@#]&@"abcb"
>True

  [1]: https://www.wolfram.com/mathematica/