Before I started studying astrology and came to understand sign positions, my mother thought that I was Capricorn.Ofcourse, I felt I could identify with Sagittarius so explicitly, but I guess I was omitting a far more serious energy than I knew/was aware of.
So when I did my first birth chart and saw that my position , as far as the Sun is concerned, was indeed Sagittarius, I started to wonder where the intense energy was coming from?
That is when I started to learn about Venus, Mars, Saturn etc. and it all started to make sense.
My Venus is in Scorpio and conjuncts Saturn-which is noted for giving a person a serious/intense disposition.
Venus, in your chart, represents what you love, find pleasurable and are drawn to.
Take note of-course that few sites will describe the Venus in Sagittarius to be all that different from Sun in Sagittarius; as they tend to use the same keywords.
Your Sun in Scorpio could be dominating your Venus love nature. Or there could be a possibility that you "downplay" this energy -because the two are so wildy different.
So, for instance, with your friends and casual acquintances that you like spending time with, you display your Sagittarius qualities; vivacious, bubbly,talkative, well-read,spontaneous etc.
But with your boyfriend, since it is such a more intimate setting and Scorpio rules this domain, you could show the more intense side to your nature; very involved, likes to dig deep, all or nothing, very loyal etc.
I do that also as when in relationships, I tend to show my Sagittarian nature and downplay Scorpio as much as I can. But in a crisis or a more serious situation, my Scorpio Venus makes it's presence felt.
The Sun is the "heart" of the chart and will progressively dominate. But that doesn't necessarily mean that the Scorpion detests horse-riding, the great outdoors, travelling, studying philosophy and broadening one's horizons(all associated with Venus in Sagittarius)
Your Venus in Sagittarian nature is there and the fact that it is also conjunct Jupiter(by sign)suggests to me that you may be failing to acknowledge something that is obvious.
Ask your friends how the perceive you in the friendship; are you the brooding, serious, dark horse?
And also ask your lover how he sees you in the relationship; are you the happy go lucky, optimistic, laughing character?
The responses may suprise you.
You are allowed to be both andmay people really are.