I know this is quite an interesting topic to discuss. Many people who are in an affair/relationship would like to know about their future whether they will be able to get married to the partner of their choice. So here is what I have learnt from different sources. Note that these combinations just indicate a love marriage and do not ensure the marital bliss or stability of marriage there after. That is a further topic and depends on totally different factors.
1. Overall the benefics (Moon, Venus, Mercury and Jupiter) must be well placed. Atleast one of these must be well placed, preferably in center (houses 1,4,7,10) or corner (1,5,9). The Lord of the ascendant must also be strong.
2. Venus naturally signifies Love and Relationship. If it is the master of 5th house (the house of romance), it will give you a romantic nature and a good chance to indulge in romance in your life.
3. If the Venus as the master of 5th house is present in 7th house, your romantic relationship will culminate in marriage, specially if master of 7th house is under aspect of/in conjunction with Venus.
to be continued...