Is it necessary that to perform Cross asset payment on stellar network sender must allow trust for that destination asset .Like We are sending USD token to receiver user that can hold only euros.
The sender of a path payment does not need to trust the asset on the receiving end of the path payment. That's the beauty of them!
I touch on this in Understanding Stellar Path Payments as well.
Path payment operations simplify the process by eliminating the need for the sender to have a trustline, and by bundling transfer and conversion into a single operation that incurs a single fee.