Jupiter is a natural benefic in Jyotish and carries significations of growth, knowledge, protection, abundance, counsel, children, dharma, and expansion. The 7th house is the primary house of marriage and committed partnership. So the logic is intuitive — put a benefic in the marriage house and good things happen.
But natural benefic does not mean "everything Jupiter touches automatically turns out well." Its functional role, condition, house rulership, associations, and timing still determine what it actually produces.
Not as a standalone rule. You will find traditions and online interpretations claiming that Jupiter in the 7th delays marriage, while classical texts also contain very favorable descriptions of the same placement. That contradiction is exactly why I do not predict marriage timing from one placement.
If marriage is delayed, I want to see where the delay is actually coming from — the 7th lord, Saturn or other restricting influences, the Navamsha, the dasha timing, or repeated delay signatures elsewhere in the chart. "Jupiter is in the 7th" does not finish that investigation.
Then the placement obviously did not mean automatic marriage. I would immediately look at whether relationship timing has actually activated yet, what the 7th lord and Navamsha are doing, whether there are delay or disruption signatures, and what Jupiter itself rules in this specific chart.
A natal placement can sit there your entire life. Events happen when the relevant structure gets activated by timing. The relationship promise lives in the whole chart, not in Jupiter alone. Jupiter in the 7th is one piece of that picture. Timing tells me when it gets turned on.
If we are talking about Jupiter transiting the 7th from the Lagna — Jupiter stays in each sign for roughly a year and crosses the 7th from the Lagna approximately once every twelve years. It is a meaningful transit. But by itself it is one piece of weather moving through the chart, not a marriage prediction.
A Jupiter transit through the 7th becomes much more interesting when the active dasha is already opening relationship material, the natal relationship factors are being triggered — the 7th house or lord, Venus, or other repeated partnership indicators — and the Navamsha supports the same relationship story. That convergence is what makes a window real. A transit alone is background weather.
Jupiter in the 7th is meaningful. Classically, it can be very favorable. But I am not going to turn "Jupiter is in your 7th" into "congratulations, you're getting married."
The placement gives me a statement about Jupiter operating through the relationship house. Then I interrogate the rest of the chart to find out what kind of Jupiter it is, what relationship structure it is working inside, when that structure activates, and what it actually produces.
Placement first. Verdict later.