"I have served many purposes and am mentioned in Quran.I have been used for falsehood, used as an affirmation and with the permission of Allah (swt) used as a cure. What am I and who do I belong to?"

The answer to your question is "the name of Allah (swt)" or "the name of God". The name of Allah (swt) serves various purposes and is mentioned in the Quran multiple times. It can be used for falsehood when people misuse or misrepresent it for personal or deceptive reasons. However, it is also used as an affirmation by believers to express their faith and trust in Allah (swt). Additionally, with the permission of Allah (swt), His name can be used as a means of seeking and experiencing spiritual healing or cure.

To find this answer, one can start by understanding the context of the question. The mention of the Quran suggests that the answer is related to Islamic teachings. By considering the different aspects mentioned (such as being used for falsehood, affirmation, and healing), it becomes evident that the answer is "the name of Allah (swt)" or "the name of God". This can be confirmed by referring to the Quran and Islamic texts, which emphasize the importance and multiple uses of Allah's (swt) name.