Answer:
They will have an Exogamous marriage.
Step-by-step explanation:
Exogamous is a custom of marrying outside own social group or class. These marriage is based on personal choices rather than culture, language, caste, religion, class etc. Exogamous is not widely acceptable across different culture and society.
There are cultures which have penalty or punishment for Exogamous marriage. Endogamus is opposite of Exogamous, where it is mandatory to marry within one´s own group, class etc.
In this case, cate is a daughter of rich father, however Harry is a poor farmer. They belong to different class of society, yet they are planning June wedding. Therefore, we can say they will have an Exogamous marriage.