Regular expression for first and last name

Question

For website validation purposes, I need first name and last name validation.

For the first name, it should only contain letters, can be several words with spaces, an

Answer 1

Fullname with only one whitespace:

^[a-zA-Z'\-\pL]+(?:(?! {2})[a-zA-Z'\-\pL ])*[a-zA-Z'\-\pL]+$