のことだからknowing him; knowing her
After a person you know well, のことだから is "knowing him" or "knowing her": going by what they are like, you say what you are sure they will do. Here it works as one piece, not as "because it is about him".
Knowing him, he's sure to come.
Kenta is always late when we meet up. Knowing him, he'll be late again today.
How to form it
Person + のことだから
彼のことだから, 母のことだから. What they are like often comes first: まじめな田中さんのことだから. A team or a company whose ways you know works too: あのチームのことだから.
- Before it
- Someone whose ways you know: family, a friend, a colleague. With no description in front, it goes unsaid: "you know what he's like".
- After it
- Your guess at what they will do or have done, usually with きっと, だろう, はずだ or に違いない.
- Tone
- Sure of yourself. Fond, admiring or resigned, depending on the habit.
- Where you'll meet it
- Conversation and writing alike.
In use
Knowing how meticulous Sato is, the materials will have been checked already.
Knowing what a worrier my father is, he'll keep phoning if he doesn't hear from me.
Do you think it's all right to leave tomorrow's preparations to her?
Misaki's so careful. Knowing her, she'll check that everything we need is there.
When it is just こと and だから
The same words can be plain こと and だから: "since it is a matter of…". "Knowing him" has a person whose ways you know in front and a guess about them after it.
It was a long time ago, so I don't remember it well.
A time in front, not a person.
It's my own business, so I'll decide for myself.
A person in front, but a decision follows, not a guess.
Close neighbours
ことだしN2
No person and no の. One reason among others, leading to a suggestion or a decision.
The wind has died down, too, so shall we get going?
らしいN4
"Just like him", "not like you": a comment on what someone has done. のことだから comes before you know.
You don't have your usual energy today. That's not like you.
Check yourself
1What does this mean?
優しい
Choose an answer to see why.
2Which sentence sounds natural?
Choose an answer to see why.
More detail
About yourself it is rueful: 私のことだから、また忘れるだろう, "knowing me, I'll forget again".
More sentences
My brother can't leave anyone in trouble alone. Knowing him, he's bound to go and help.
Yumi can keep a secret. Knowing her, she won't let this slip to anyone else.
My little brother loves anything new. Knowing him, he's sure to have tried that model already.
That team has so much experience. Knowing them, they'll deal calmly with anything unexpected.