Answer by Japanese teacher
(1) is a direct way of asking the hotel staff for permission to leave your luggage at the hotel.
For (2) and (3), the sentences are left hanging and they are supposed to be said with hesitation. This is a useful technique in Japanese communication to express something that is not said verbally.
In this case, the “non-verbal” meaning is the sense of apology for the inconvenience incurred on the listener.
Upon hearing this apologetic tone, the listener would be more receptive and agree to your request.
It is not easy for English speakers to use this kind of “non-verbal” communication initially but they are very useful in getting things done.
You will get the hang of it with more practice.