Oral or verbal agreements are generally enforceable (though note: an agreement to pay a pre-existing debt of a person must usually be in writing, though an agreement to repay someone for a debt or cost that *will* incurred--e.g. to pay 1/2 of the next 2 month's rent--may be oral). The issues, of course are: 1) Proving the terms, or even the existence, of the agreements if the other person disputes them. The burden of proof will be on you, as the one suing, to prove the agreements--though small claims court is inexpensive, so it's not much of a risk to sue in it.2) Even though small claims court is inexpensive, it's not free and it can take up time; if it's going to simply be your word vs. hers, with no other witnesses or evidence in your favor, consider whether it is worthwhile given that the burden of proof (see above) is on you.