Grammar JLPT Level N3 - Lesson 15

Structure of さ (Casual よ):

Phrase + さ⁽¹⁾

⁽¹⁾ さぁ、さあ、さー

Details about さ (Casual よ):

さ is a 感動詞(かんどうし) (interjection) in Japanese that has three primary uses. These are as follows:
誘(さそ)い、促(うなが)し - To invite, incite, or draw attention to something.
驚(おどろ)き、当惑(とうわく)し - The express surprise, confusion, or bewilderment.
話(はなし)の流(なが)れを抑(おさ)える - To control or keep in check the flow of a conversation.
In this lesson, we will be focusing on a specific feature of the first meaning (to draw attention). Unlike other types of drawing attention that さ is able to be used for (see this grammar point), this さ will only appear at the end of sentences. Here, さ is almost identical in meaning to that of よ, with a slight added nuance of high confidence in what one is saying.

彼氏(かれし)がもう私(わたし)のことを信用(しんよう)できないってさ。
My boyfriend told me that he can't trust me anymore. (Added confidence gives the nuance of 'can you believe it!')
インスタで見(み)たんだけど、キヨミの赤(あか)ちゃんが明日(あした)生(う)まれるんだってさ！
I saw it on instagram, but I heard that Kiyomi is going to give birth tomorrow.
そんなこと心配(しんぱい)ないさ!俺(おれ)に任(まか)せとけ！
Such a thing is not necessary! Leave it to me! (Trust it to me in advance, so that it is not a problem later)

さ (Casual よ)

Usage Notes for さ (Casual よ):

This さ is primarily used by men, and can vary in meaning depending on the speaker's tone of voice. However, in almost all situations さ will mean 'what I just said is correct' (sometimes angrily, sometimes informatively, and even sometimes in a completely carefree way).

お前(まえ)さ...
You… (Are you freaking serious)
たかし君(くん)も行(い)きたいってさ。どうしよう？彼(かれ)も招待(しょうたい)する？
Takashi-kun said he wants to go too. What should we do? Should we invite him too?
そんなの俺(おれ)にだってできるさ。分(わ)からないけど。
Although I am not certain, even I would be able to do something like that.