Ms. Revathi,
The concerns you've raised are pretty genuine.
These are purely my personal views, and I take total responsibility for whatever I say here:
I really do not know what your experience is like; however, I must tell you that you need sufficient standing, maturity, and, above that, as a professional, you should enjoy unquestionable respect both within and outside the organization to effectively handle an exit interview.
In fact, some people (who don't want to close the doors for the future, who might look at a return back) will give you a balanced and honest feedback - positive and those that weren't (with constructive suggestions too).
The converse is true too, that there will be some who are so excited about their new job that they will be critical of everything they experienced being with you.
There is another category too which will only gloss over the whole thing, sound good and sweet, and may not tell you the truth too and cry for every reason of emotion to convey their departure.
Anyway, for your evaluation, you will need to have some sort of background information on such employees as to what their contributions were when they were with you, what their attitude was like, etc., to probably arrive at some good conclusions. And then there must be a process by which the information is shared with those who are at the decision-making table to ensure concerns, if any, are addressed, in order to reduce, if not be able to arrest attrition.
You will be well advised to take a detailed read of this too:
exit interviews - tips for interviewers, employees, sample exit interviews questions and answers guide
Here are some more links for your information:
Sample Survey Employee Exit Interview Employee exit interview including an evaluation of the relationship with co-workers, The Job, Benefits, and company evaluation.
http://aia.org <link fixed>
This might lead you to more questionnaires on Employee Engagement, Employee Satisfaction, etc.:
Employee Satisfaction Survey Questions: 3 Sample Templates You Can Use Today | Qualtrics Blog