Since you love each other you should marry her 

2) you also had physical relationship with her 

3) caste is immaterial 

4) however if you want to break off the engagement take the plea that your fiancée has suppressed material facts about their  caste and hence you are breaking off the engagement 

If girl files case of rape against you take the plea that it was consensual sex with her 

The mere caste as the reason to break the engagement is atrocious. 

Nevertheless, since it is your personal choice you have got every right to do this.

Breaking an engagement is not crime. However physical relationship on understanding of future marriage is considered as a rape. So remain vigilant on this. 

breaking an engagement generally doesn't have legal ramifications, and it's not considered a crime, though it can lead to financial disputes over gifts and expenses.

The Karnataka High Court has ruled that breaking an engagement does not amount to a false promise of marriage or cheating, and it's not grounds for prosecution under Section 376 (rape) of the Indian Penal Code (IPC).

If you're sure that the engagement isn't right for you, it's important to move forward with breaking it off as quickly as possible.

It will not affect your employment however you may take precautionary measures in case she plans to lodge false criminal complaint against you with police.

You can marry her to save this relationship as well your career. 

You cab save the messages exchanged with your fiancée 

file NOC with police regarding her threats to commit suicide 

you issue a legal notice to her to refrain from indulging in illegal activities of threatening you with suicide or any other harm to you or your family members.

you may communicate your decision to call off the proposed marriage and break the engagement fo the reasons you rely upon. 

You can say that false information was given to you and on basis of that you are calling off 

- As per section 65 of Indian Contract Act, any person who has received any advantage under such agreement or contract is bound to restore it, or to make compensation for it to the person from whom he received it.

- Further as per section 73, when a contract has been broken, the party who suffers by such breach is entitled to receive, from the party who has broken the contract, compensation for any loss or damage caused to him.

- Further, the party who broke the contract due to mistakes of other party will have also bear the consequences for breaching the contract as well. 

-  Further, breach of promise to marry also attracts an offence of cheating under S. 415 of the Indian Penal Code, if the intention was not to marry at the time of engagement.  

- Since, you wanted to broke the engagement due to the concealment of true facts by the bride family , hence you are not responsible for the same , and the bride family will have to prove the existence of promise of marry. 

- Hence, send a notice to her family and return the gift , ring etc. received at the time of engagement , and further you are not responsible to pay the cost of engagement legally. 

- You can lodge a complaint as information to the police for the threatening of committing suicide 

Ultra‑brief guide

1. Engagement ≠ marriage – you can call it off; at worst they may sue for expenses.

2. Keep all WhatsApp chats – screenshot & back‑up; they protect you against false suicide or rape claims.

3. Suicide threats – immediately inform local police in writing/SMS; it shows you took preventive steps.

4. Return gifts/expenses (optional but wise) – reduces dispute.

5. Have a lawyer send a formal notice – ends contact and records your stance.

Section 69 of BNS.

Sexual intercourse by employing deceitful means etc.

Description

Whoever, by deceitful means or by making promise to marry a woman without any intention of fulfilling the same, and has sexual intercourse with her, such sexual intercourse not amounting to the offence of rape, shall be punished with imprisonment of either description for a term which may extend to ten years and shall also be liable to fine.

Explanation: “deceitful means” shall include the false promise of employment or promotion, inducement or marring after suppressing identity.

BNSS Classification

• Imprisonment which may extend to 10 years and fine.
• Cognizable
• Non-bailable
• Triable by Court of Session

It is for you to decide your future as a Gov. servant. Punishment is jail up to ten yrs. 

1. The Legal Status of Engagement in India
   Engagement is a religious and social understanding, but not a legally binding agreement in Indian law. Either party can terminate the engagement at any moment prior to marriage without any form of liability. There is no breach of promise to marry law or damages exclusively for wrongful termination of engagement.
   
   2. How to Legally Break the Engagement
   You can advise the girl and her family in writing (preferably by way of a legal notice) that you do not want to continue with the marriage. Return the gifts or costs incurred on account of the engagement to avoid future quarrels. It is recommended that there be a written mutual settlement or admission that neither party has any claims against the other to avoid future harassment or legal proceedings.
   
   3. Issue Regarding Caste and Social Barrier
   Though caste is a social consideration, as per law it is not an aspect to force or nullify an engagement or marriage. It is your right to call off the engagement owing to caste issues, but stand ready for anticipated social or familial retribution.
   
   4. Physical Relationship and Concerns of Government Job
   Having had a physical relationship on agreed terms, it does not amount to legal obligations to get married. There is no legal requirement to marry because of physical encounters. Being a government worker, there is no immediate legal penalty for calling off the engagement, but be watchful for any social or work-related repercussions.
   
   5. Threats of Suicide and WhatsApp Messages
   Save and store all WhatsApp messages and any other proof of threats or abuse. Suicide threats are serious; you might want to report to local authorities or apply for protection orders if you are threatened. You can also further choose to register a police complaint for criminal harassment or intimidation if the threats persist. It is best to see a lawyer right away to shield yourself from any form of false accusations or coercion.
   
   6. Potential Legal Risks and How to Avoid Them
   The family of the girl or the girl herself may attempt to lodge complaints like dowry harassment or defamation. If you have not harassed her or demanded dowry, these complaints can be rebutted. Document all communication and keep away from using abusive or threatening language. If false cases are lodged, you can approach court for quashing of FIRs and apply for anticipatory bail if required.
   
   7. Practical Steps to Take Now
   Issue a notice through a lawyer to legally call off the engagement and make your stand clear. Save all records of threats or harassment. Avoid face-to-face confrontation; allow your lawyer to deal with correspondence. If threatened or harassed, register a police complaint and avail yourself of legal protection. Seek advice and counsel from a family law attorney.