希望 and 願い: preferences and wishes
Distinguish who wants something from its fulfillment when stating preferences or describing wishes.
Stating a preference
希望, read きぼう, can mean hope or a preference. 午前中の面接を希望します。 requests an interview in the morning as the person's preference.
An instruction to enter 希望する日時 asks for the desired date and time. It does not mean that the appointment is already confirmed.
Something one hopes will come true
願い, read ねがい, is a wish or something one hopes for. 家族の幸せが私の願いです。 expresses a wish for one's family's happiness.
願いがかないました。 says that a wish came true. 願いがかなうといいですね instead expresses the hope that it will come true, without confirming a result.
The person wishing and the person acting
本人の希望を聞きました。 says that someone listened to the person's preferences. It does not also establish that the listener approved them.
友人の願いをかなえたいです。 expresses wanting to fulfill a friend's wish. Distinguish what the friend wishes for from what the speaker wants to do.
Does submitting 希望する日時 confirm the date and time?
Show the answer and why
No. It communicates a preference. Confirmation requires separate information.