先生は初心者にも分かるように懇切に説明してくれた。
The teacher explained it kindly and thoroughly so that even beginners could understand.
係員の懇切な対応に感謝の手紙を書いた。
I wrote a letter of thanks for the staff member's kind and attentive service.
この参考書は例題の解説が懇切丁寧で評判がいい。
This study guide is well regarded for its careful, detailed explanations of the example problems.