Why is に used with causativeて+もらう but not causativeて +くれる?


**Example:**

> 両親 **が** 一人で日本に行かせてくれた

> My parents let me go to Japan alone

_And_

> 両親 **に** 一人で日本に行かせてもらった

> My parents let me go [after me asking] to Japan alone




くれる basically means "to give", and もらう basically means "to receive". Let's
think about this with simpler examples:

  * 両親が私 **に** 本をくれた。  
My parents gave a book **to** me.

  * 私は両親 **に** 本をもらった。  
(= 私は両親 **から** 本をもらった。)  
I received a book **from** my parents.

In the former, the subject is 両親, and in the latter, the subject is 私. Both
has に, but these two に play different roles. When you use もらう, the に-marked
argument marks the **giver**. This is a basic rule of how もらう works.

Now, if we replace 本を with 一人で日本に行かせて, we get these:

  * 両親が(私 **に** )一人で日本に行かせてくれた。
  * (私は)両親 **に** 一人で日本に行かせてもらった。  
(両親から no longer works because no physical object is transferred.)

These are the sentences you are asking about. In the latter, you can see the
に-marked argument still marks the **giver** (of favor).




くれる basically means "to give", and もらう basically means "to receive". Let's
think about this with simpler examples:

  * 両親が私 **に** 本をくれた。  
My parents gave a book **to** me.

  * 私は両親 **に** 本をもらった。  
(= 私は両親 **から** 本をもらった。)  
I received a book **from** my parents.

In the former, the subject is 両親, and in the latter, the subject is 私. Both
has に, but these two に play different roles. When you use もらう, the に-marked
argument marks the **giver**. This is a basic rule of how もらう works.

Now, if we replace 本を with 一人で日本に行かせて, we get these:

  * 両親が(私 **に** )一人で日本に行かせてくれた。
  * (私は)両親 **に** 一人で日本に行かせてもらった。  
(両親から no longer works because no physical object is transferred.)

These are the sentences you are asking about. In the latter, you can see the
に-marked argument still marks the **giver** (of favor).

