clients want you to say "100 % fixed" even
Yeah in IT, and networking I say it "Should be fixed". I refuse to use absolutes as good ol' Murphy's Law likes to play with us. Also the people we deal with are not technical enough to know if a new problem came up and even if the old problem is fixed all they care about is whether it is working or not.
As to software I tend to say "that bug is fixed", but I make it clear until it goes through testing that I cannot guarantee another bug was not created somewhere, though whether I say that or not really depends upon the complexity of the software. If it isn't too complex I just say "it's fixed".
I really try to avoid absolutes as they can be almost like a tech person's superstition and ATTRACT unwanted problems.
The famous thing of never bragging about how secure your site is. :)
Yep, that sounds alot like what I do.