Always ask for references

This is also where your "third party" comes in handy. Not only will they be able to be your reference, they can also check out a prospective mate's references. A reference can include an Imam who knows the brother who proposed to you, a sister who knows the woman you may want to marry well, a family friend, a boss, a co-worker, and/or business partner.

A note about honesty and references: the people you ask may know something not very nice about your prospective spouse. Remind them that if they reveal this information, they would not be backbiting from the Islamic perspective. In fact, in the case of seeking marriage, complete information should be given about an individual, both good and bad.

The advice of one of the companions of the Prophet, Umar Ibn al-Khattab can help in this regard:

A man came to Umar ibn al-Khattab and spoke in praise of another. Umar asked him: "Are you his nearest neighbor such that you know his goings and his comings?"

"No."

"Have you been his companion on a journey so that you could see evidence of his good character?"

"No."

"Have you had dealings with him involving dinars and dirhams (money) which would indicate the piety of the man?"

"No."

"I think you saw him standing in the mosque muttering the Quran and moving his head up and down?"

"Yes."

"Go, for you do not know him..."

And to the man in question, Umar said,

"Go and bring me someone who knows you."

(quoted from Islam The Natural Way by Abdul Wahid Hamid, p. 66)

This gives you three types of people you can ask about a prospective mate's character: a neighbor, business colleague or someone who has traveled with them.