Hello Jugal
I went into the lab to check this out, because it sounded strange to me. I tried creating an OSPF neighbor adjacency between an NBMA and a P2MP Non-Broadcast network, but the adjacency did not come up. This makes sense because neither of these network types automatically send hellos to the broadcast address because they’re not broadcast networks.
However, if you configure the neighbor command on one of the two, then the adjacency forms. This is because the router configured with the neighbor command will begin sending unicast hellos to the configured destination. The neighbor receiving them will respond with unicast hellos to the source address. So with only one neighbor command configuration between the two, an adjacency will form.
Take a look at this NetworkLessons note that details the various OSPF network types for more info.
I hope this has been helpful!
Laz