The reversed Ace of Swords represents a very difficult opportunity. Its esoteric meaning is that of a difficult start. This aspect suggests that you will need to be prepared to face challenges in order to achieve your goals. This means that you will need to consider all possible pros and cons before making a final decision.

The Tower represents a period of extreme change and the need to change things quickly to achieve the desired goal. This indicates that you may face challenges as you try to balance keeping and selling the gown. You may also find that you will have to make compromises between your decisions and the family's needs regarding the wedding dress.

Finally, the Ten of Wands represents the end result of the situation. This means that if you are to achieve a positive outcome, you will need to be ready to face challenges and be flexible in making wise decisions. The Ten of Wands tells you that you will eventually get what you want, but you must be willing to work hard to get it.

In conclusion, the tarot cards suggest that you need to consider all aspects before deciding whether to sell or keep your sister Giovanna's wedding dress. You will need to carefully weigh all possibilities to ensure balance between the family and your decisions. The cards also suggest that you will be able to achieve your goal if you work hard towards it. So, my recommendation is to keep your sister Giovanna's wedding dress, as it shows that you intend to respect her family's wishes and express your love and care for her.