I actually wondered about that but thought I'm overthinking it, completely forgetting that in a marriage question venus would be her secondary significator and indeed, she is interested in a marriage, not in a fling, and this was her specific question. Hm... Was this used in the past? I don't recall ever seeing it written but this means nothing, it can always work. Well, now I'm dying to see if and what will happen this year!!!
Well Lilly uses it in chapter 49 Book II but he's a bit imprecise. he assigns the additional significators (Venus for her, Sun for him) He explicitly says that for a woman querent the significators are the Ascendant and his Lord, the Moon and Venus and says that the querent has three significators and the party desired has three significators and lists five possible ways the matter might perfect.
1. Ascendant ruler or the Moon is in the seventh
2. The planet the Moon separates from applies to the same planet the Moon applies to
3. the Sun and Venus apply to each other
4 Lord 1 in the seventh or Lord 7 in the first
5 Any translation of light between the significators.
Now I usually take (1) to mean that the querent desires marriage but not that it will necessarily effect the matter. (4) appears to be a partial repetition of (1) and (3) appears to require a mutual application of Sun and Venus, which can only happen if Venus is Retrograde. However I think he simply means it can either be through Venus applying to the Sun, or the Sun applying to Venus (when Venus is slowing or stationary).
But (5) seems to fit the situation in this horary.
Lilly previously refers to 'Alkindus' (Al-Kindi) and gives some aphorisms, of which the first is Lord 1 applying to Lord 7 (or vice versa) and the second is
'if the Moon doth apply to Venus and she is strong, increasing in her motion and in some of her of her own dignities, and the Moon likewise, the marriage shall be concluded
Now in this case we might not need anything more. Venus is in her own triplicity, terms and face and she is direct, swift and in a good house. The Moon is in her own exaltation and in a mutual reception with Venus by domicile. She is swift and in a good house. Her only defect is that she is waning. So is that enough to end the matter. I would not have thought so but it does cast a doubt. But on Al-Kindi's argument the answer should be that they will very probably get married (the Moon waning counts only -2 in the Medieval scheme). But remember Chanah's experiences with a New Moon or near New Moon.
My view is that there's no way you can say the answer is 'No' with these testimonies. But I don't think you can guarantee a 'Yes' or give an unequivocal 'Yes'. Highly likely but not completely cast iron, seems to be the conclusion.
At least that's better than your initial judgement, so we've shifted things around.