Astrology is based on the position of the planets and their influence on our lives. Venus is considered the planet of love, romance, beauty, and luxury. When placed in the 8th house for Sagittarius lagna, it can bring about some significant changes in one's life.
In this placement for Sagittarius lagna, Venus is in a neutral sign state. This means that its effect on the native won't be too positive or negative. It will be moderate, but still impactful.
Firstly, as Venus is lord of the 6th house (the house of debt/illness) and 11th house (the house of gains), it will take care of these houses. Therefore, there might be some debts that the native has taken on recently which will start getting settled by their own efforts or with some support from friends or colleagues. Gains through work efforts will also flow and might bring some financial stability in life.
Secondly, Venus is natural karaka (significator) of the 7th house (the house of marriage/partnerships). With this placement in 8th House for Sagittarius lagna, it can delay marriage or cause some instability in existing relationships until mid-30s. If Sun/Rahu combination exists at the same time then they may face issues regarding self-esteem or assertiveness causing lot of troubles within relationships.
However if Mars/Sun aspect Venus from fourth house at same time they may bring success to their professional life!
Those who are already married may face challenges due to partner’s illness/poor health situation either their partner having poor planetary aspects over his/her natal chart resulting into tough times from partner during critical periods.
Thirdly, Venus' aspect on second-house causes discomforts regarding oral health/food & drinks area but nevertheless overall money inflow increases thereby indicating good financial gain through freelance projects/inherited assets etc
In conclusion, Venus is a planet that has a significant impact on our lives, and its placement in the 8th house for Sagittarius lagna can bring certain changes both positive and negative. With this placement, it is important to focus on taking care of one's health and avoiding any confrontations with their partners during difficult times. Though eventually success will be achieved based purely on efforts with little assistance from people around. And also they are bound to have more financial stability in life thanks to their efforts & some supportive networks over time.