c.Validation.Email(email)と書く
app.go
func (c App) MypageConfirm(email string, message string) revel.Result {
name := c.Session["userName"]
c.Validation.Required(email).Message("Email is required")
c.Validation.Email(email).Message("Please enter in email format")
if c.Validation.HasErrors(){
c.Validation.Keep()
c.FlashParams()
return c.Redirect(App.Mypage)
}
return c.Render(name, email, message)
}

うん、良さそうではある