"more than happy" is a correct and usable phrase in written English. It is a way to express that you are very pleased and eager to do something. For example, "I am more than happy to help you with the project."
He was more than happy to oblige.
More than happy to make amends, Kai.
We're more than happy today".
"I'm more than happy now," Robert concludes.
I'm more than happy with my lot.
He was more than happy to help.
I'm more than happy with him.
More than happy to cooperate with everyone.
"We're more than happy," he said.
"Now they're more than happy to talk".
They are more than happy to haggle.
Thanks to Ludwig my first paper got accepted! The editor wrote me that my manuscript was well-written
Listya Utami K.
PhD Student in Biology, Bandung Institute of Technology, Indonesia