It's awfully dense. Some points:
this does not necessarily assure [ensure] that they will always choose the right spouse for their children.
• verb 1 tell (someone) something positively to dispel doubts.
• verb 1 make certain that (something) will occur or be so
children can bring gratefulness and honor to their family.
It is not clear what you think “gratefulness” means ; children can bring honor to the family and show OR express gratitude to their parents.
Bring and return gratitude is not good English – we show OR express gratitude
The third advantage is that parents can end a very big and important duty in their life.
Is this advantage one of the arranged marriage or one for the parents? It seems to me to be more an advantage for the parents.
When there is an increase of divorce rate, the number of widows will
Widows are women whose husbands have died. Do you mean “divorcée(s)”? If so, then for the purpose of your argument you need to rewrite this paragraph using that word or the phrase “divorced mothers” or “divorced women”,