I know that だよ is like the informal of です but I couldn't get it because when I
was having a conversation with someone which went like this

> person: うん痩せたいです今よりもっと  
>  me: 私も... ;;  
>  person: **だよなー**

I couldn't get it
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2013-06-28T04:50:55.587
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2022-05-02T18:33:53.277
2022-05-02T18:33:53.277
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question
meaning colloquial-language
What does だよなー mean?
If you've learned enough of the language to use Kanji and such, you should
know that だよなー is not a single unit, but 3 separate components. The だ in that
is the 'casual,' so to speak, iteration of です, and is the one you're more
likely to see in less formal situations and by more casually-minded folks. The
latter 2 parts are what's known as 終助詞(しゅうじょし), the end-of-sentence particles
that give a sentence a different flavor and intent, the kind depending on
which one is used, much like the exclamation point, question mark and 'man' do
in ending an English sentence. In this particular case, this is a combination
of よ(emphatic 終助詞, works like '!' or 'Yo') and な(variation of ね, tag 終助詞 that
also functions as a softer version of よ)

With all that established, your little chat likely went something like this:

> Friend: Yeah, I wanna drop some pounds. Today, especially.  
>  You: Me too...  
>  Friend: Totally, man
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2013-06-28T05:19:18.533
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2013-06-29T03:43:12.040
2013-06-29T03:43:12.040
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answer
`だよなー` is manly tone of `'だよねー'`.

`だよねー` is `だよね`.  
`だよね` is shortly word of `そうだよね`。

same following.

> person: うん痩せたいです今よりもっと  
>  me: 私も... ;;  
>  person: やっぱり、そうだよねー。

* * *

Example.

```

    friend: 痩せたいよ今よりもっと。  
    me    : 私も... ;;
    friend: だよねー。 / だよなー。 / そうだよねー。 / そうだよなー。
    
    
    junior: 痩せたいです今よりもっと。  
    me    : 私も... ;;
    junior: ですよねー。/ そうですよねー。
    
```

ですよなー。 / そうですよなー。 are wrong.
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2013-07-13T13:03:07.640
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answer
Roy Fuentes' answer is pretty good, but needs some correction. な is not adding
softness. It's adding emphasis. I felt this wasn't clear in his answer. Also,
ね is not a softer version of よ.

Addressing some of the comments — thinking about whether だよなー is more
masculine or feminine is a bit overthinking in my opinion. Either gender can
say it in a casual setting (I think young people use this more than older
people).

よ sort of adds emphasis, or simply is used when telling someone something,
like you're figuratively handing them information. It can be used casually or
formally.

な here is just emphasis. It doesn't seem formal to me. Casual, familiar. A
little bit "young" like the "man" in "yeah, man!"
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2016-09-26T13:55:29.183
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answer