Anjan,
I am not sure, but I get the feeling that you did not like the responses you got here, so now you want to close the discussion.
Part of our growth in life is taking on board what other people say about us, and working out whether what they say is applicable or not. You appear to be rejecting everything other people have said, without critically examining yourself, and asking if there is something there that might be holding you back.
I note that you have spent the majority of your training in one organisation. I am not suggesting that, in itself, is a bad thing, but you need to look at this from the point of the interviewer. What are they looking for? Are you reading the job specification properly, and CAN YOU MEET the requirements they seek?
Training is an interesting career. First and foremost the essential skill a trainer must have, is the ability to COMMUNICATE, as Dinesh and others have pointed out. If you cannot communicate, you cannot train. End of story.
That is a simplistic view of course, as trainers also need a lot of other skills, such as being able to think quickly on their feet, being able to meet the learning requirements of each individual learner in the group, and dealing with diverse personality types for example.
By your own admission, you are telling us you believe you are failing interviews because you cannot articulate your skills and abilities to the interviewer?? I would respectfully suggest, that if you are repeatedly failing at interviews, then you are applying for jobs you are not suited too, and do not meet the requirements.
You also mention that these jobs you are applying for are Training Manager jobs. A Training Manager needs a lot more skills than just being able to stand up in front of a group and train. Maybe this is where you are falling down. By my definition, a Training Manager needs to be able to plan and implement training programs, as well as lead, train, and motivate a team of trainers to deliver that training for an organisation.
By your own admission, you might be an excellent trainer, but if you haven't got the management skills, then you won't get the job.
I would suggest you go back to basics, and decide what it is you really want to do. Secondly, do a thorough assessment of all the interviews you have presented for recently, and critically analyse what went wrong. What did these employers want that you couldn't deliver on? What skills and experience am I lacking? What do I need to do to be successful in future interviews?
None of this is rocket science. The ball is in your court.