I am writing a romance book. In it one of my character's recites a portion of the Dhammapada. If I publish my book, will I be violating any copyright laws? How would I go about getting permission to put the quote in my book?
This is a contentious issue in Buddhism because the Buddha taught the Dhamma is to be given freely & because the translators are only translating rather than creating anything original. To quote:
This is the best of gifts: the gift of Dhamma.
The easy solution is to simply change of few words and claim it as your own translation.
If the Buddha was alive, he would say: "Frankly, my dear, I don't give a damn".
I think you mean "legally allowed", which isn't really a question about Buddhism (for example maybe it would be more on-topic at writers.se).
Anyway my understanding is that copyright laws vary from country to country. Ancient works might not be copyright, but modern translations of those works might be copyright.
You might find "copyleft" or "public domain" translations, for example here.
You might assume (correctly or incorrectly) that quoting a small portion counts as "fair use" and use it (possibly with attribution and without prior permission).
Or, getting copyright permission might be a job for your publisher (unless you self-publish).
Otherwise I think you get copyright by contacting the copyright-holder (who is usually identified, in a publication) and asking for permission.
When one uses Dhamma for commercial purposes, on does nothing good for one self and for others. If one uses Dhamma to even increase unskilfull ideas, not only to make benefit from others greed (after love here) and spreads wrong view, using it, its even more worse.
And there is nobody who could ever give you the permission to make commercial use of the Buddhas Dhamma. Everybody doing so, is involved in a thief (in measures of Dhamma). So knowing such one might maybe seek for a dealer and fence or, after wise considerations change either this or that.
Here a such a live-story of same case in fencing: On Human Right, Kamma and trade with Dhamma. They are not of much shame and if not public the trades in Dhamma, do it discrete and most would do on even if telling, even deliberatly knowing it.
One is the way in the world and on Nibbana, its not possible to take the other with it and that is what is the place of gaining path: by letting go of what gives just short pleasure.
One can ask at the worlds biggest and most succesfull public fencing place of Dhamma but there are also other around, sometimes more near.
(Note: This is a gift of Dhamma and not meant for commercial purpose or other wordily gains)