Tapu then and now for Ichcha

I was really surprised to see ichcha who use to say Tapu is her best friend to "Bahut hi giri hui/ghatiya soch wali insaan" actually I didn't understand why she didn't deduce this when she married Veer in her place or when she tried to get her killed and why this time. Can somebody change so suddenly overnight without going through a phase of disbelief ?

Probably best explaination is logic doesn't really work in Uttaran. What do u guys think ?

that is the only explanation for Icha changing her tone n tune! Finally seeing Tapu for what she is!