Difference between 完成させる and 完成する (transitive usage only)


Again, I am not referring to the intransitive usage of 完成する.

> **Examples**
>
> 文を完成させなさい。  
>  文を完成しなさい。
>
> 夢を実現させた。  
>  夢を実現した。

From my understanding of the grammar, させる implies that you could be making
other people help you along as well, but I'm not sure, it seems like in the
example sentences there shouldn't be much nuance differences.




Most Sino-Japanese words could originally be used both transitively and
intransitively, some even as all verb, noun and adjective, as they are in
Classical Chinese. But since they have been more and more Japanized, many of
them were assigned a fixed grammatical status like other native words.

完成 is almost _exclusively intransitive_ nowadays. Dictionaries _may_ say it's
also transitive, but that usage has nearly died out in actual world (though
not incomprehensible). Thus, if you'd like to use 完成 transitively, you should
choose 完成 **させる**.

実現 still retains the ambiguity, so unfortunately you're not able to know if a
実現する is "to realize" or "to be realized" without help of context. In your
case, 夢を実現する is not ambiguous (because it takes を), but 夢を実現させる allows two
interpretations: "realize one's dream" or "make one realize one's dream".

