Difference Between Commitment Letter & Bond

I went for an interview in one company. They asked me if I can sign one year bond according to which if I leave the job before one year then I will have to pay 3 months salary back. But I politely refused & told them that though I plan to work long term for the company I can't take risk and guarantee it because you never knows what happens in future. So they told me that they will not insist on signing bond if I am not comfortable but at-least I will have to sign a commitment letter. I said yes at that time. But you may find it stupid but I really don't know what commitment letter is? All I assumed that it must not have any conditions like bond. But does commitment letter have any condition? I am selected and will be joining next week so I still have the time to think

And please tell me if signing commitment letter is safe or not? Does it have any terms & condition breaking which any action can be taken against you or it is just a formal letter signed by the new joinee

Such conditions mean its a contract. If you sign, whether is called a bond, a commitment letter or terms and conditions, you are liable. If the conditions do not favour, approach the H.R. to vary some conditions, without Which you don't think you will sign.
If the company insists on getting you to work for year GUARANTEED and it doesn't favour you to do so, it is better you don't accept/sign the offer rather than being engaged in a legal tussle later.
Godfrey Tom

A good idea is to immediately ask the hr for a copy of the commitment letter
Check out what it says.
If it has the same terms as a bond, then reject it
incidentally a bond for payment of money in case you have not worked for a year is of no value in cases where the company has not spent money in training you. There are lots of court decisions to support that.
That apart, I agree with your contention that signing a bond tomwork for a certain period is a bad idea.
However, if you now decide not to join, what will you do ? You will be out of job

Tell the HR you want to work for the company and would be very useful to the company. Of course, any employee will contribute well only if he is happy working for the company - if the person is forced to work, it would be like bonded labor - you can possibly get them to break stones by forcing them (even that is illegal and inhuman), but you cannot get any creative or original work from anybody by forcing him to work for you.
Also tell the HR commitment letter or bonds make you scared. Tell her you'd wonder why is the company not confident that it would be able to retain its employees just on the strength of quality of work and work environment.
Don't sign any commitment binding yourself to any company.