You are using hashes but you should be using objects to create object (I am assuming mass-assigment is turned off as by default) do:
basic_profile = BasicProfile.new
basic_profile.name = 'Samir'
user = User.new
user.password = '123'
user.email = 'aba@gmail.com'
user.basic_profile = basic_profile
NotificationsMailer.welcome_facebook_user(user).deliver
or turn mass-assign off and do
NotificationsMailer.welcome_facebook_user(User.new({:password=>'123',:email=>'as453now@gmail.com',:basic_profile=>BasicProfile.new({:name=>'Samir'})})).deliver