확 is a mimetic word used to describe "spreading of wind, smell of fire"
딱 has many meanings
1. (갑자기) suddenly
그가 들어오자 아기가 울음을 딱 그쳤다
The baby suddenly stopped crying when he went in.
그를 보는 순간 숨이 딱 멎는 것 같았다
I thought my heart would stop the moment I saw him.
2. (정확히, 꼭) exactly, just, precisely, perfectly
계산이 딱 들어맞았다
My calculations were exactly correct[right on].
입사한 지 딱 1년 되었다
It's been exactly a year since I joined the company.
두 사람의 이야기가 딱 들어맞는다
The accounts of the two men square with each other perfectly.
옷이 정말 딱 맞네요
The clothes are an excellent fit.
3. (오로지, 단지) just
딱 한 마디만 더 할게요
Let me just say one more word.
딱 한 번만 용서해 주세요
Please forgive me just this once.
4. (달라붙는 모양) close(ly) (옷이) tight(ly)
바지가 너무 딱 붙는다
The pants are too tight.
그들은 항상 딱 붙어 앉는다
They always sit close together[to each other].
5. (단호히) flatly, simply
딱 잘라서 거절하다
refuse flatly[simply]
딱 잘라서 거절하다
give a flat[point-blank] refusal
모른다고 딱 잡아떼세요
Just tell them you don't know anything at all.
6. (아주, 몹시) very, really
거만한 사람은 딱 질색이다
I really hate arrogant people.
그런 일은 딱 질색이다
That's the kind[sort] of thing I hate the most.
In case of,딱 한번이에요.
딱 means "just"
딱 한번이에요.
"Just this once"