The phrase "able to fully understand" is correct and usable in written English.
You can use it when discussing someone's capacity to comprehend information or concepts completely.
Example: "After the training session, the participants were able to fully understand the new software features."
Alternatives: "capable of completely grasping" or "able to comprehend fully."
His mother believed in her husband's philosophy, but was never able to fully understand it.
Yet we are not able to fully understand the relation between the subjects.
What's more, I'm still learning the language, and being able to fully understand many of his reputedly incisive double and triple entendres still seems a long way off.
"We're a family channel, but we're very cautious about sensitive topics that small children might not be able to fully understand," he added.
In addition, authors of the new Science paper say there are some risks that scientists may never be able to fully understand.
"It appears that Intrado was not able to fully understand the significance and breaadth of the problem until around 2 a.m.
Sensory and consumer scientists are seeing the need to explore broader measures, such as product-driven emotions, to be able to fully understand and satisfy consumers' demands.
Since agents are an active part of the base structure of an organization's business and processes, they should be able to fully understand that structure.
Its symptoms were rage, isolation, secretiveness, and a proclivity for repressive action, and its cause was a war whose necessity only Presidents and their advisers, it seemed, were able to fully understand.
"What a device like this with Cuneiform writing is doing in Austria is something that no one is able to fully understand or explain," writes conspiracy site To The Death Media.
For me, the dilemma of forced treatment is an issue of access to care, and should be based on whether an individual is able to fully understand the nature, risks, benefits and alternatives of treatment, or of refusing that treatment.
