The other answers are OK for when you want to display the string to the user. The user can't really tell the difference between a "real" dash and the unicode trickery.
But, if you really must have the dash (e.g. because that string is used as a password somewhere, or as a url key for an API) then you can just use this format:
The dash is a punctuation mark that is similar to a hyphen or minus sign, but differs from both of these symbols primarily in length and function. The most common versions of the dash are the en dash (–) and the em dash (—), named for the length of a typeface's lower-case n and upper-case M respectively.