Lords of the fifth house and lagna are associated in the same house.
When both lords of lagna and the fifth house aspect each other powerfully.
If the lord of the lagna and fifth house are in parivarthana mutual exchange of houses.
Fifth house aspected or occupied by a strong planet Moon Mars and Venus.
Malefic planet situated in the 9th house. 9th house denotes custom usage and family tradition.
It is said that if Mars, Venus have exchanged their relative positions in the horoscope of a couple occupy each other's "Navamsaka" the love marriage will prove to be successful one.