Learn Farsi: همین پرتره بی‌نظیر است.

Using hamin adds emphasis. While in portre just means "this portrait", hamin portre translates to "this very portrait" or "this exact portrait". It highlights that you are talking about this specific one and no other.

Does hamin become plural if we talk about multiple portraits?

No. Just like regular demonstrative adjectives such as in (this) and ân (that), emphatic adjectives like hamin (this very) and hamân (that very) never take a plural suffix when they come before a noun. You would say hamin portrehâ for "these very portraits".

What is the literal breakdown of the word bi-nazir?

It combines the prefix bi- (meaning "without") and the word nazir (meaning "equal", "peer", or "match"). Literally meaning "without equal", it is the standard way to say "unique" or "peerless" in Farsi.

Why does the word portre sound so much like English?

It is actually a loanword from the French word "portrait". Farsi adopted many French terms during the 19th and 20th centuries, especially for the arts, sciences, and modern daily life, so you will often recognize them.