Asking about a person’s past
Question

                As-salam wai lai kum,
 When helping brothers/sisters to find
      suitable Muslim partners, what questions can be asked, and what is forbidden to ask ?
     Can one ask about their past when they were
      non-Muslim or not practicing Muslims ?
  Can one ask ones wife/sister to describe in
      detail the appearance of an intended wife or describe in detail to them regarding a
      brother ?
     Was Salam
Praise be to Allah.If you want to look for a wife for someone, or a husband for a woman, then
    you can ask him about his wishes, such as the desired age, level of education, employment
    situation, country and origin and position of the family, and whether he has any
    preferences about her general appearance, such as skin colour, height, etc. The most
    important characteristic to ask about is a person’s level of commitment to Islam.
    This kind of useful question is fine.
But asking for details of a person’s past and wanting to know what
    sins they might have committed when they were ignorant about Islam – this is not
    right at all. Allaah covers people’s sins and loves to see them covered (i.e., not
    dragged out into the open). So long as a person has repented, his sins have been wiped
    out. Islam deletes whatever came before, so why should we ask questions that will only
    embarrass people? Allaah accepts people’s repentance without their having to confess
    or expose their sins to any other person. A number of the Sahaabah had committed adultery
    and murder repeatedly, or had buried infant girls alive, or stolen things, but when they
    entered Islam they were the best of people. No one needs to be reminded of a shameful
    past; it is over and done with, and Allaah is the All-Forgiving, Most Merciful. What
    matters when considering a person for marriage is how that person is now: is he righteous
    or not? Has he cut all ties with his past and his wrong deeds, or not? If he is clearly
    living a good and righteous life now, then it is wrong to dig up the past. If there is any
    fear of anything that could have future implications, such as certain diseases and so on,
    then there are medical tests which can give the answer and put your mind at rest.
As far as giving a detailed description of a prospective wife to someone
    is concerned, this can be done in writing: one of her mahram relatives (i.e. a blood
    relative to whom marriage is permanently forbidden) or a woman who knows her can write
    down a description, then a trustworthy person can deliver it to one who is seriously
    considering a marriage proposal. The Prophet 
 (peace and blessings of Allaah be upon
    him) said: “No woman should describe another woman to her husband as if he can see
    her.” (Reported by al-Bukhaari, 4839)
    The wisdom behind this prohibition is the fact that a
    husband might like the sound of what he hears, so he may divorce the one who described the
    other to him, or there may be temptation to do wrong. (Commentary on the above
    hadeeth in Fath al-Baari).
    We ask Allaah to help us all to do that which He loves and
    will earn His pleasure. May Allaah bless our Prophet Muhammad.