I can only but try.

[Odessa Dawn]

Using I can only but try in speech, where could I take a short pause, please? I think it occurs after only, do you, please?

​

 

[5jj]

I see no need for any pause in those four words.

Incidentally, 'I can but try' seems far more natural to me.

 

[emsr2d2]

"I can only try" and "I can but try" are both fine, but "I can only but try" is unnatural.