The part "it will be understandable" is correct and usable in written English.
You can use it whenever you want to point out that something will be understandable, for example: "The instructions are clear and easy to follow, so it will be understandable."
If he still cannot feel anything today, only this time because he has had too much to drink, it will be understandable.
*In light of readers' comments, I want to clarify a point: given the Knox family's legal bills, it will be understandable if she now elects to sell "her story" — without going beyond that to parlay her celebrity into a multi-media all-about-Amanda-thon.
"I have been treated wrongly and I was not happy with it and I think that it will be understandable if one day I decide to leave Liverpool".
We feel that the writing and presentation can be considerably improved so that it will be understandable to all interested readers.
It's also important to remember that just because a tweet can theoretically be accessed doesn't mean it will be, nor does it mean the underlying sentiment will be understandable to an outside audience.
So, you need to think about how to sort through it, take out the excess, and arrange it so that the situation at the case site will be understandable to your readers.
A few non-New Orleanians have failed to get it, but while I usually hope my work will be understandable to everybody, D*U*C*K isn't really for them.
Professor Barabasi's well written book will be understandable to most readers, but its core concept takes a moment to absorb.
So there will be understandable tension next month when the ruling Opec body meets in Vienna and its member states fight over what to do.
"The first inescapable and appalling consequence is that he [Hodgson] has been in custody for 27 years as a consequence of an unsafe conviction, old wounds have been reignited... for the victim's mother in particular, and there will be understandable public concern about the extraordinary circumstances of this case".
