Thank goodness your sister was saved from this fake relationship. For a time, she was heartbroken, but the prosperous life ahead will make her forget all her sorrows and pains. Did you know that life had to save her from a big test, that's why she went through this test.
Because if her true nature was revealed after marrying this person, then it would have been a great trial for your sister. In such a scenario, there is an example of "a ditch ahead and a well behind" and it is a very painful moment for a woman.
Best wishes for your sister.