Jupiter sextile Venus, natally means that how the person reaches out to life and to network is compatible with their relating style. Sometimes this includes a certain degree of personal tolerance and/or charm. But the sextile is a weak influence.
In synastry, sextiles are even weaker. It indicates that the Jupiter person is tolerant and generous to the Venus person ... but of course, the stronger aspects have to also support this for it to have much effect.
Jupiter is often called the planet of "luck", but really all it is, is an indication of being tolerant, optimistic and able to recognize opportunities ... self-created luck.
Luck is not activated. We either act on our opportunities or we don't.