Well, this is your opinion, mine is different. Saturn's face is in the last 10 degrees, he is within. He is dignified although yes, will be in term slightly later, hardly a problem really as she doesn't need to be dignified as she is already engaged. And dignity systems differ - Ptolemy, Dorothean, etc. Them being in the same house foretells conjunction, hardly a better option could there be. 6th is a placement that signifies service and everyday life and I've written on this forum a number of times about significance of 6th house when people are actually going to face everyday life together. It is not all 5th house romance and 7th house agreements. Reality hits afterwards. Again, they do not need at this point to prove anything, they are engaged. Positive aspects between luminaries are always a good omen in horary and Sun and Venus are co-significators in questions about marriage. Mercury is a natural ruler of contracts and agreements and is in the house of contracts/agreements and marriage while Virgo is intercepted in the house of family. Jupiter is excellently placed in a very favourable house, if you take it as 11th (why flip the chart???) the house of wishes and God's will delivered actually. As 5th house, it is equally explicit. I even wonder if there is pregnancy in the picture or a very serious consideration of it. I really wonder what else is needed.
To add, the Moon will connect the Sun (through sextile) with Venus (through square) to boost! These are her two upcoming aspects. So, all significators and co-significators will connect. yes, the marriage will happen.
Overall, it sounds you are seeking a denial of the marriage in the chart but I simply don't see it.