Hello Sara,
We are happy to welcome you for the honeymoon.
The weather is very good in july, not so hot, you can enjoy the hole day at the beach.
At the hotel we accept euro, USD,... ans visa card. If you have to take your visa on your arrival, better to come with some USD. To do shopping in many shops you can pay with dollar or euro, but if you have local money (tanzanian shilling) it's better to avoid to wait a lot to get your change or to loose it. You can exchange in many places in town.
We have been booked for a honeymoon cottage, when we 'll do the final location, be sure you ll get a nice room.
Best regards
Myriam