We need a long time to prove that others and things (1) don't give us happiness. Most people believe that happiness is always related to marriage and it is the only way to rescue them from loneliness. But it has been found that those who were lonely before marriage are still feel (2) so alone and who were sad (3) before marriage are continuing to live life of sorrow after it. The marriage shock for many persons belongs to this wrong concept. It is the illusion that makes many people pursue it, flittering from marriage to marriage and from relationship to other, seeking a perfect partner who could bring pleasure and joy to their lives but they will discover lately that this ideal partner could exist only in their minds.
In short, happiness can only BE made by us. Perhaps some people surrounding us contribute to make us happy for awhile but if we are incapable to create happiness inside us, no marriage, nor children, friends, family or jobs can concede it.
Okay then, let's see...
1- others and things makes the sentence look a bit strange, don't get me wrong, but I dunno why.
2 - still feelling alone
3 - those who were sad
Done, I belive that's all, but, am not sure.
Student or Learner