What act is performed to demonstrate sincerity after taking the obligation?

The correct answer highlights the significance of a solemn and heartfelt commitment represented through the act of kissing the Holy Bible, which is a traditional gesture within Masonic rituals. This action symbolizes respect for the sacred texts and a deep personal vow to uphold the values and responsibilities associated with the obligation taken. It serves not only as a physical act of sincerity but also reinforces the moral and ethical obligations that the individual has just promised to honor.

In Masonic practices, the Holy Bible is not just a book; it is a symbol of truth and guidance. Therefore, kissing it twice signifies the commitment to adhere to the principles it embodies, showcasing a deep sense of integrity and seriousness about the obligations undertaken.