Answer:
Dennis found it hard to believe that they could work so well despite their cultural differences
Step-by-step explanation:
Cultural differences often present a challenge in a relationship as it usually means that the compatibility between two people (in this case iroquois and dutch) is low. Religion, manners, values and perspective are complete opposites in this particular case however their relationship is able to blossom despite all of this factors hence why Dennis was surprised at the odds of the relationship working out.