どうしてもjust can't; no matter what
どうしても is "whatever I do". Before a negative it is "I just can't": you try, and it doesn't work. Before a wish or a need it is "no matter what": nothing else will do.
just can't
I couldn't get to sleep last night, however hard I tried.
no matter what
I want to go to this concert no matter what.
Just can't
どうしても + a negative
Mostly a "can't": どうしても思い出せない, どうしても起きられない, どうしてもわからない.
No matter what
どうしても + a wish or a need
どうしても行きたい, どうしてもほしい, どうしても行かなければならない. Other words can come in between.
Can't help
どうしても + something that just happens
どうしても緊張してしまう, どうしても時間がかかる.
You try, and you can't
This is the everyday "I just can't", for a name that won't come, a night without sleep, a feeling you can't get past.
I just can't remember that person's name.
I simply cannot believe that he would break his promise.
I have something that day that I just can't get out of, so I can't come.
A standard way to turn down an invitation.
With a plain negative it is "just won't": a door that sticks, a child who refuses.
This door just won't open.
My son just won't eat vegetables, whatever I do.
No matter what
There is something in this town that I really want to see.
This job has to be finished today, no matter what.
In a request it is pressing: you are asking the other person not to say no.
I really need you to be at tomorrow's meeting.
An invitation is ぜひ, not どうしても.
Not said: どうしても
(Please do come and see us.)
ぜひ遊びに来てください.
It happens whatever you do
With something nobody chooses, it is "can't help" or "inevitably".
Before a test I can't help getting nervous.
A job you are doing for the first time inevitably takes time.
どうしても～ない or とても～ない?
Both are a strong "can't". どうしても～ない is about the effort: you try, and it still doesn't work. とても～ない is a verdict on the thing: it is too much for you, and you can say so without trying.
I did my best, but I just couldn't eat it all.
After trying.
とても～ないN3
"Can't possibly". Here, said at the sight of the plate. It needs a "can't" after it: "just won't" is どうしても.
I couldn't possibly eat this much.
Close neighbours
どうにも～ないN1
With a "can't" it means the same, with more of a sigh: nothing to be done. どうしても is the commoner, and only どうしても takes a wish.
I just couldn't get to sleep last night.
Check yourself
1What does this mean?
どうしても
Choose an answer to see why.
2Which one fits?
うちの
Choose an answer to see why.
More detail
どうしてもと言うなら is "if you insist".
If you insist, I don't mind helping.
More sentences
There is something about his explanation that I just can't accept.
This is the one match I want to win no matter what.
On winter mornings I just can't get up.