Venus is the goddess of love. It is her responsibility to see that all sentient creatures find their loves, or at least gain confidence as far as romance goes. This role has evolved over the eons, as her original purpose was simply to ensure procreation among species. As such, she works closely with Palutena and oversees the love fairies, including Kyu.
As the goddess of love, she argues she can't limit herself to one lover, and as such is quite amorous. This has a tendency to make other deities take her less seriously.