Convince me to book my flight.

Im planning on visiting Rio as a solo traveler. I’m a young woman and planning to be staying in a super nice castle hostel. I plan on being at the beach every day for the week in there. But how do I enjoy the beach without constantly worrying about leaving unattended items and getting robbed? I want to enjoy my stay to the fullest extent. I know the basics like not being too flashy; but how do I literally go to the beach the whole day and want to bring my towel, sandwich, phone, sunscreen? Should I even go? I really want to go it’s my dream; plus I’m in argentina so it’s convenient for me to go it’s not a long ways. Thank you