Search any aspect list and you might expect five pages for the QSun and RVenus. In a real birth chart, three of them never happen. Venus cannot get far enough from the Sun to sextile, square, trine or oppose it. What you can have is a conjunction, and two minor aspects that are worth knowing about.
How far Venus can get from the Sun
Venus orbits the Sun inside Earth's orbit. Seen from Earth, it swings back and forth on either side of the Sun and never gets very far. Its greatest elongation is about 47 degrees, and the interpretation library behind this site puts the limit just under 49 degrees. Either way, it is short of 60.
That rules out the sextile (60), square (90), trine (120) and opposition (180). No natal chart has these aspects between the Sun and Venus, so readings of them are theory, not experience.
The three contacts that can happen
Conjunction. When Venus is within about 8 degrees of the Sun, the two are conjunct. This is the one major aspect they share, and it is common. It ties your values, affection and taste into your identity, often with artistic talent and strong social charm. Read the full page: Sun conjunct Venus.
Semi-sextile (30 degrees). When Venus is about a sign away from the Sun, within a tight orb, you have a semi-sextile. This is a mild, supportive minor aspect. It is read as a small boost to artistic ability and to expressing affection smoothly, the kind of contact that helps quietly rather than defining you.
Semi-square (45 degrees). At its widest, Venus can sit about 45 degrees from the Sun, which forms a semi-square, a minor hard aspect. It is associated with low-level friction around pleasure and desire. Some people with it feel a restless or rebellious streak in how they want to enjoy life, or subtle tension between what they value and how they present themselves. It is irritation more than crisis, and it often pushes you to define your own tastes rather than accept inherited ones.
If Venus falls between these points, say 15 or 38 degrees from the Sun, the two are not in aspect. That is ordinary.
What this means in practice
First, Venus's sign is always within two signs of your Sun sign. A Sun in Gemini person has Venus somewhere from Aries to Leo. So the contrast between your identity and your style of love is always limited.
Second, if you feel a strong conflict between who you are and what you want in love or money, it is not coming from a Sun-Venus square, because there isn't one. Look at aspects to Venus from Mars, Saturn, Uranus, Neptune or Pluto, or at Venus's house.
Third, the side of the Sun matters. Venus ahead of the Sun in the zodiac rises after it and sets after it, an evening star. Venus behind the Sun rises before it, a morning star. Many astrologers read morning-star Venus as bolder and quicker in affection, evening-star Venus as more considered.
Questions people ask
Should I pay attention to a Sun-Venus semi-square?
If it is within a degree or two, yes, as a minor note. It will not dominate your chart, but it can explain a stubborn itch around pleasure or self-presentation.
Can transiting Venus square my Sun?
Yes. Your natal Sun is fixed, and transiting Venus moves all the way round the zodiac, so it can make any aspect to your natal Sun. That is a short transit, not a natal aspect.
Is Mercury limited the same way?
Even more so. Mercury stays within about 28 degrees of the Sun, so the conjunction is its only major aspect. See Sun and Mercury aspects.
Check your aspects
The Aspects tab in your birth chart lists every aspect with its orb and whether it is applying or separating, so you can see which of these contacts, if any, you have. For more on the semi-square and other small angles, read minor aspects: quincunx, semi-square and quintile.