Ending a sentence with から unusually...

[Shiroisan]

As far as I was taught, から means from and from alone, just with many variations: "After", "and then", and at the end of a sentence, it can be translated as "because" ("from" this fact, we say the following fact.)

Knowing this, I'm still unsure of Genki's useage in the last chapter's dialogue. At the time I sort of skimmed past it because it didn't really effect my comprehension, but I always found it odd and now I seek clarification. Here are the two examples:

母：　　　メアリーがいなくなるとさびしくなるね。
メアリー：　でも、来年大学を卒業したら、また日本に戻ってきますから。

um... ok, why would you use "since", "because" or "from" at the end of the sentence if that's the only statement you're saying. It randomly cuts off there as they start talking about something else.

メアリー：　じゃあ、そろそろ行かなきゃ。
たけし：　メアリーが卒業して日本に戻ってくるまで、待っているから。

And this dialogue uses it in the exact same way as the previous. It's as if they're about to go on to say something else after から ("So don't be sad" or something to that effect perhaps) but they never say it so it sounds awkward and cut off.

Can anyone share any insight on this?

[yangmuye]

This is just my own feeling, please tell me if I were wrong.

から means something like:
分かってほしい
分からなくても、とりあえず受けてほしい
異議があっても、黙っていて、反発しないでほしい

Simply speaking: 私の言うことは絶対だから。

Spoiler:

Using ～ないんだからね to end up a sentence is a characteristic of ツンデレ.
んだ makes a strong, but not so forceful declaration, and is usually used to correct other people's thoughts. It is also a phrase frequently used by children and females.
However adding から makes it very firm or even arbitrary, sound like an insistence.
ね softens the sentence, makes it sound like a matter of course, and everyone would agree that.

待っているから。

Here から means 絶対約束を守る.
Using any 終助詞(e.g. ぞ, よ, ぜ, の(だ)…) usually makes the sentence softer, but using から is even firmer and stronger than the plain form.


I like this SS. から also frequently appears in phrases such as だから。いいから。(私が)言ったからって。

Spoiler:

http://ayacnews2nd.com/archives/51618307.html

男「あ、見えた」
女「・・・彼女連れでそういうこと言うかなぁ」
男「何が？」
女「だからぁ」
男「(チアの次に行進してる消防隊を差して)ほら、あのトランペットの人、高校の先輩なんだ」
女「え」
男「え？」

[Shiroisan]

分かってほしいと言うことのような意味ですね。そこまでしか分かっていません。

I couldn't follow the rest unfortunately.　However, if I understand that it's like that, is that enough? If so, it makes sense to me.

[yangmuye]

It usually means, what the speaker said is definite, absolute or must be obeyed, and the speaker don't want the listener to oppose him in any case.

The listener will just end up the topic no matter he understand/agree or not.

[Shiroisan]

Thanks yangmuye!

[Ranja]

母：　　　メアリーがいなくなるとさびしくなるね。
メアリー：　でも、来年大学を卒業したら、また日本に戻ってきますから。

メアリー：　じゃあ、そろそろ行かなきゃ。
たけし：　メアリーが卒業して日本に戻ってくるまで、待っているから。

When a sentence ends with から, something is omitted or implied.
In the first example,
また日本に戻ってきますから, (すこしの あいだ だけ、がまんして ください/それを きたいして、まっていて ください or something like that).
At any rate, it suggests that the [来年大学を卒業したら、また日本に戻ってきます] part is some consolation to the fact of [メアリーがいなくなるとさびしくなる].

As for the second example, what is omitted is less obvious.
In this case, just think that it attaches some nuance of "Remember this(=that I'm waiting)" or "Keep this in mind".