You did promise to marry her and that has become a big problem. Try to convince her through friends. If not then try to ask her to wait. Does she want to marry you as soon as possible? 

Well, then that is what you should do. Wait for as long as you can wait and in the meantime she may change her view. 

I don't think she'll kill herself. She'll attempt to do it so that you are implicated. 

Dear Sir,

Tell your partner you care about them, but stick to your boundaries. Giving in to threats over and over does not make a relationship healthy, and it only creates anger and resentment on your end. You could say something like, “You know I care about you very much, and I understand you’re upset right now, but I will not _____.”

Put the choice to live or die where it belongs – on your partner. You can’t be responsible for another person’s actions, no matter what – and this includes when your partner chooses to be abusive. An optional response is: “I think our relationship should be based on love and respect, not threats. I really care about you, but this is your choice and I can’t stop you from making it.”

Remember that no matter what your partner says, you don’t have to prove anything. Even though they might be saying something like, “If you really loved me, you’d stop me from killing myself,” the real truth is that there are unhealthy patterns in your relationship. Until those unhealthy patterns are addressed, they will most likely continue no matter how many times you give in to your partner’s demands.

If your partner often says they’re going to kill themselves when things aren’t going their way, they’re not showing you love – they’re likely trying to control your actions. If this is the case, consider the tips above and try to get help where you can. You might try talking to a counselor or other professional therapist if that’s an option for you. But remember, you are not your partner’s counselor, and you can’t force your partner to get help if they don’t want to. They have to make that choice for themselves.

Don't get afraid about petty issues like this, You're not even married to this girl, this gives you a lot of immunity from false cases like rape or threaten and things. Here is a list that you need to keep ready before the cops meet you ( It might even happen so let's consider that use case too )

1. All the conversations with this girl regarding the job offer ( SMS / WhatsApp / Emails ). Take screenshots and save emails as printable pdfs.
2. All the conversations with the guy during the interview / resume in case any communication that has been done.
3. Clear indication of message that describe the threat this woman is falsely claiming. If it happened in a phone call, don't take her calls anymore. Just message her, "I am busy right now, please message me about what you want to talk, ill reply when i get some free time" . This will lead her to type it out clearly that she will file a case against you.

Now you're fully ready to deal with this situation. Things like these don't get to theFIR stage in the country(India) without any solid proofs ( can only happen if she bribes the cops too much ) if the man is a working professional and educated.  If she bribes them too much and cops are not listening. Give a copy of all these proofs to your friends and ask them to call the Media the moment cops file an FIR and make it a public issue. Cops will be forced to release you as its a false case and there is no solid proof from the girl.

Never ever get scared of shitty people because of their shitty threats of cops when you're running a startup. You have the courage to start a company which only a few have. Don't let anyone touch that courage by trivial issues. There is more REAL shit coming for you when your start up becomes big. Work towards the success.

Dear Client,

When a girlfriend or wife threatens to commit suicide, in such cases, a case of Criminal Intimidation can be filed.

According to various case examinations, all girls who threaten their husband or boyfriend of suicide never commit it. It is advised to visit, police station and speak to the station officer or inspector about it. Inform local SHO of the police station and inform him through an application stating that this girl is having suicidal tendencies and you should not be held responsible in case such a thing happens. Inform the same to her parents and also to make her attend counseling.

Thankyou.

Hi, It is better tried to convince her.... If you take any legal action then you will face adverse problem.

You had sex with her under promise of marriage 

2) if you refuse to marry her she can file case of rape against you under section 376 of IPC 

3) you can take the plea that it was consensual sex with no promise for marriage 

You cannot be forced to marry against your wishes 

but be prepared if she files  criminal case against you of cheating and rape 

It is your call whether you want to marry her or not 

It is your call whether you want to marry her or not 

If your girl friend really commits suicide with a suicide note left behind stating that you are responsible for her decision to commit suicide since you cheated her with the false promise of marriage, you may be in a very deep trouble.

As you both were in an intimate relationship too, hence naturally there may be evidences left behind to substantiate your relationship with her. 

Therefore it is advisable that you talk to her reconcile the differences and on a compromise note you may leave her company with her consent without inviting any trouble that you anticipate.

If she is threatening you that she will send the video or audio to your parents, you may better decide to reveal all the facts to your parents in advance before she tries to spoil your name or career. 

You may also keep your parents in your confidence and narrate all those things that took place between you both and inform your decision to them that you may not be able to marry her but she is insisting you to marry her and all the details.

Your parents perhaps may talk to her  or her parents and try to bring some solution to this problem.

You may not have to reject her offer out rightly but you can handle it in a more gentle way and convince her or try  to adopt the strategy of your parents getting involved in this to rescue you from this problem somehow. 

- Supreme court declared that , when  a man and a woman in love live together , is part of the right to life and not a criminal offence, and further live-in relationships is legal in India.

- Since, the said girl is black mailing your brother in the garb of relationship, hence her such act is against the law.

- You can lodge a complaint/information with police for your safety against her for extortion under section 384 of IPC, and for threatening to implicate in false cases and also for threatening to commit suicide. 

File a police complaint that she is threatening you. It will help you if she files any false complaint

You should immediately get in touch with some lawyer and take steps to defend you from any future cases filed by her.

I would not advise you to file for anticipatory bail as of now has no complaint or FIR has been registered but a complaint for criminal intimidation can be filed against her at this stage.

She cannot coerce you into marrying you against your wishes. You should try to settle the issue with her first and if that is not possible then you should retain a lawyer for this case 

Her waiting would not create any difference as you have decided that you do not want to marry her at all but it can buy you sometime.

Try to get some audio video evidence of her where in she is trying to blackmail you.