laravel mass asignment tapi request relasi one to one

klo bukan mass asignment kan codenya : $profile->name = $request->name , contohnya.. klo modelnya mass asignment kaya gini ane coba ga bisa, biar bisa gimana ya ? soalnya ane masukin insert biasa error ditanya builder::profiles() pasti.. klo pakai mass asignment gini bisa

 $user = User::with('profile')->findOrFail($id);
      if ($user->profile === null)
      {
          $profile = new Profile([
                        'name' => 'test'
                      ]);
          $user->profiles()->save($profile);
      }
      else
      {
          $user->profile->update(['name' => 'test']);
      }

user hasOne profile profile belongsTo user

jadi ane pengennya dinamis bagian kode name => test tergantung form blade nya nantinya, gimana yaa ?