Questions & Answers about Sen yalnız bir kadınsın.
Why is bir in the middle of yalnız kadın?
How does the ending -sın work on kadınsın?
The suffix -sın means 'you are' for a single person. Because the last vowel in kadın is an undotted 'ı', the 4-way vowel harmony rule means the suffix must also use 'ı'. That is why it is kadınsın and not kadınsin.
If kadınsın already means 'you are a woman', do I have to use the word Sen?
No, it is optional. You could just say Yalnız bir kadınsın and it would still mean 'You are a lonely woman'. Adding Sen at the start just gives a little extra emphasis to the subject.
Does yalnız mean 'alone' or 'lonely'?
It can actually mean both! In Turkish, you figure out which one it is from the context of the sentence. Here, 'a lonely woman' makes the most sense as a description.