Difference in nuance between causative form and てもらう


This question is inspired by [this
one](https://japanese.stackexchange.com/questions/48773/how-do-you-say-to-get-
someone-to-do-something-in-japanese) (unanswered at the time of writing).

> それは田中さんに教えてもらってください。  
>  Get Mr Tanaka to tell you that.  
>  それは田中さんに教えさせてください。  
>  Make Mr Tanaka tell you that.

I feel that in English there is a difference between 'make someone do
something' and 'get someone to do something'.

'make someone do something' feels like a stronger statement. It leaves no
doubt that you expect the person to do something. Whereas, 'get someone to do
something' feels more like a favour i.e. you can ask them to do something but
you shouldn't expect that they will do it.

How about my two Japanese sentences above? Is there a parallel argument when
choosing either causative or てもらう, or do these sentences feel the same?

_btw I'm never sure when to use に or を with causative form. Please correct me
if I got these sentences wrong._




～せる・させる used in the sense of 使役* can sound stronger and more forcible than
～てもらう and I think it usually leaves no doubt that you expect the person to do
it. ～てもらう sounds softer and less forcible but I think you'd usually still
expect that they will do it.

One more difference in your two sentences is, 教えてもらってください clearly shows that
the recipient of the favor is the hearer ("Get Mr. Tanaka to tell _you_
that"), while 教えさせてください sounds like the person taught by Mr. Tanaka will be
someone other than the hearer ("Make Mr. Tanaka tell _them_ that").

Another example:

> 田中さんに書いてもらってください。  
>  田中さんに書かせてください。

書かせる sounds stronger and forcible. You'd usually use this for someone of lower
status (e.g. 田中さん is your inferior/後輩 or subordinate/部下), but not for someone
of higher status. **

書いてもらう sounds softer and less forcible. You could use this for someone of
lower, equal or higher status, but I'd recommend using honorific
expression/尊敬語 for your boss/superior, e.g. 書いていただく**.

*～せる・させる used in the sense of 放任・許可 ("let someone do~; allow someone to do~") doesn't sound as strong, e.g. 「田中さんに書かせてあげてください。 / 書かせてさしあげてください。」 

**Exception: In business situation, you'd use ～せる・させる for someone of higher
status in your in-group when talking to someone of your out-group.)

* * *

As to when to use に or を with causative form: You're using it correctly.
Basically you use に when the verb is transitive (and also when the verb is
intransitive but takes を, as in 道を歩く). For more details: [Causative Form -
Difference between 子供に本を読ませる and
子供を本を読ませる](https://japanese.stackexchange.com/q/33510/9831)




～せる・させる used in the sense of 使役* can sound stronger and more forcible than
～てもらう and I think it usually leaves no doubt that you expect the person to do
it. ～てもらう sounds softer and less forcible but I think you'd usually still
expect that they will do it.

One more difference in your two sentences is, 教えてもらってください clearly shows that
the recipient of the favor is the hearer ("Get Mr. Tanaka to tell _you_
that"), while 教えさせてください sounds like the person taught by Mr. Tanaka will be
someone other than the hearer ("Make Mr. Tanaka tell _them_ that").

Another example:

> 田中さんに書いてもらってください。  
>  田中さんに書かせてください。

書かせる sounds stronger and forcible. You'd usually use this for someone of lower
status (e.g. 田中さん is your inferior/後輩 or subordinate/部下), but not for someone
of higher status. **

書いてもらう sounds softer and less forcible. You could use this for someone of
lower, equal or higher status, but I'd recommend using honorific
expression/尊敬語 for your boss/superior, e.g. 書いていただく**.

*～せる・させる used in the sense of 放任・許可 ("let someone do~; allow someone to do~") doesn't sound as strong, e.g. 「田中さんに書かせてあげてください。 / 書かせてさしあげてください。」 

**Exception: In business situation, you'd use ～せる・させる for someone of higher
status in your in-group when talking to someone of your out-group.)

* * *

As to when to use に or を with causative form: You're using it correctly.
Basically you use に when the verb is transitive (and also when the verb is
intransitive but takes を, as in 道を歩く). For more details: [Causative Form -
Difference between 子供に本を読ませる and
子供を本を読ませる](https://japanese.stackexchange.com/q/33510/9831)

