How to say welcome in Jèrriais depends on who the person or persons being welcomed are:

Sai l’beinv’nu = Welcome (masculine singular informal)
Sai l’beinv’nu en Jèrri, Jînmîn! = Welcome to Jersey, Jim!

The welcome has to agree with the person who is welcomed:

• Jé n’tais pon l’beinv’nu = I wasn’t welcome (m)
  Jé n’tais pon la beinv’nue = I wasn’t welcome (m)
  Ou n’tait pon la beinv’nue = She wasn’t welcome
  Jé n’têmes pon les beinv’nus = We weren’t welcome

Sai la beinv’nue = Welcome (feminine singular informal)
Sai la beinv’nue en Jèrri, Sûzon! = Welcome to Jersey, Sue!

Séyiz l’beinv’nu = Welcome (masculine singular formal)
Séyiz l’beinv’nu en Jèrri, Moussieu l’Président! = Welcome to Jersey, Mr President!

Séyiz la beinv’nue = Welcome (feminine singular formal)
Séyiz la beinv’nu en Jèrri, Madanme la Présidente! = Welcome to Jersey, Madam President!

Séyiz les beinv’nues = Welcome (feminine plural)
Séyiz les beinv’nues en Jèrri, mesdanmes! = Welcome to Jersey, ladies!

Séyiz les beinv’nus = Welcome (masculine & mixed plural)
Séyiz les beinv’nus en Jèrri, mêssieurs! = Welcome to Jersey, gentlemen!
Séyiz les beinv’nus en Jèrri, mesdanmes et mêssieurs! = Welcome to Jersey, ladies and gentlemen!

But a welcome is feminine:

Faithe la beinv’nue = to wish someone welcome, to greet
La Minnistre fit la beinv’nue ès membres dé l’associâtion = the Minister made a speech of welcome to members of the association

Also faithe bouonne vénue:

• I’ lî fîtent bouonne vénue = They made him welcome
  J’ai ieu eune bouonne vénue à la caûchie = I had a welcome at the harbour

Jé n’tais pon l’beinv’nu = I wasn’t welcome