③ I'd like you to have this book, if you haven't got one yet.
「もしよければ、この本を差し上げます」
（※すでに本を持っている可能性が大きい場合）は、
① Please use this book, if you don't have one.
② This book is for you, if you don't have one.
③ I'd like you to have this book, if you haven't got one yet.
などがオススメです^^
If you'd like, you can have this book. / If you don’t mind, I’d like to give you this book.
「もしよければ、この本を差し上げます」という表現は英語で "If you'd like, you can have this book." や "If you don’t mind, I’d like to give you this book." と言います。
例えば、 "If you'd like, you can have this book." 「もしよければ、この本を差し上げます。」
または、 "If you don’t mind, I’d like to give you this book." 「もし構わなければ、この本を差し上げたいです。」
アメリカ合衆国 
