Yes, a written agreement between two parties will up hold in court. * Maybe. It depends upon the validity of the all the terms that are contained in the written agreement. ** Regardless of the ability for the written agreement to stand up in court (which is to say the fact it is written only makes it easier to PROVE to a 3rd party the claim of a debt being owed, NOT that one actually does exist and needs to be repaid),...by the question you agree there is both a debt and an agreement. 1) For every moral, legal and self respecting reason, one should try to uphold their agreements, certainly not evade them. 2) Not repaying a debt is essentially the same as stealing. If it isn't clear, stealing is a bad thing. (So one lies to get enriched, still a form of theft like deciet or trickery, instead of strong arming and running).