Recall that infinitives are verbal nouns.
In one idiom in Hindi, infinitives can be “possessed” by a pronoun or postposition.
Consider the following examples:
उसका कहना है कि दो सौ से अधिक लोग आये थे – “He says that more than two hundred people came”
उसका कहना था कि पिछले साल सौ लोग आये थे – “He said that one hundred people came last year”
उसका मानना है कि अगले साल इससे ज़्यादा लोग आयेंगे – “He believes that even more people will come next year”
मेरा मानना है कि बहुत लोग आनेवाले हैं – “I think that a lot of people are going to come”
Notice how, in each of the examples, an infinitive is “possessed” by another word: उसका कहना, उसका मानना, मेरा मानना.
Literally, this is “His saying is…”, “His believing is…”, “My believing is…”. This can be translated with a noun, as in “His claim is…”, “My belief is”, or with a verb phrase, as in “He says that…”, “I believe that…”, etc.
The possessive indicates agency; it indicates who or what does the action of the verb.
Consider a few more examples:
उसके जाने से पहले मैंने उससे बात की थी – “I spoke to her before she left”
सर्कार ने दो जवानों के मार जाने का दावा किया – “The government claimed that two soldiers were killed”