You are wrong because Indian women are a very strong cricket team. If you check the women's ICC rankings, India women's team is number 3 according to ICC ODI ranking and India women's team is number 3 according to ICC T20 ranking. India women team lost few matches against Australia so you consider that team as weak team? It is true that India lost the series against Australia, but they recently played very well against the West Indies women's team and defeated the West Indies team. The Indian women's team has won almost all the matches against the West Indies women's team, so it can be said without a doubt that the Indian women's team is a very strong cricket team.
ICC rankings can be misleading. According to the ratings, South Africa is at no.4, and India is at no.3. But honestly, I don't think that India is stronger than South Africa. India's higher ranking can be partially explained by two factors - first of all, most of India's recent matches have been against weaker teams such as West Indies. And secondly, India perform better while playing at home. In a few days, the next series for India women is also against another weaker team - Ireland Women. And this series is also scheduled to be played at home.
India is definitely a strong one. Now India is stronger compared to South Africa in their home ground, sure. But is India actually stronger when it comes to playing overseas? I don't think so.
If I remember correctly, the last time Indian women had actually played against South African women was in India. And I thought India should have had a far better performance compared to what they have shown. I'll admit, the ODI series was one-sided and condensing performance from India, the t20 was a different story.
Anyway, that was played in India. I really do not think the Indian women's team is actually as powerful when they step outside India. I have also seen a common pattern with the Indian women's team. They are pretty good when playing against weaker opponents. But they continuously struggle while going against strong opponents who actually pose a threat. Especially when they are playing in overseas conditions. I think South Africa is going to be a big threat to them.