Answer:
Yes Jill can sue Jack if certain conditions are in place
Step-by-step explanation:
From indication, Jack and Jill had an oral form of agreement, and understanding. This implies that each party ought to keep to their part of the agreement. If Jack then defiles the rule of the agreement, Jill can take it up in court if evidence of the oral discussions can be established, especially in terms of the amount that was agreed upon and the date it was reached.