Throughout BB we saw Shukla tried flirting with Devo, shefali bagga n even mudhurima. All 3 r strong-headed women, who were not taken in by Shukla n his so-called charm.
On the other hand you have emotionally vulnerable women like Rashmi, shenaaz and Arti who don't seem to have a strong emotional support from their close ones or/ and have faced such situations that have made them emotionally fragile n hence they r more susceptible to shukla's so called charm. And shukla prey's on their this vulnerability. He looks down upon them, humiliated them but still they can't seem to break free from him completely. I guess now Rashmi is, but she too at times seemed to fall for him.
And now it's proven again with shilpa, So basically Shukla tries to charm his way n the emotionally strong females keep away from him, knowing he is toxic n the emotionally vulnerable females fall for him, coz for them he's giving them the attention they carve for.