Vikas points to a woman and says, "She is married to my father's only son." How is the woman related to Vikas?

Break down the statement made by Vikas:
"My father's only son" $\to$ Since Vikas is a male pointing out his father's only son, he is talking about himself (Vikas).
"She is married to... [Vikas]" $\to$ The woman is married to Vikas.
Therefore, the woman is Vikas's wife.