This proverb means that great trust has been placed in you, similar to how one would trust a lock to ensure the security of a house during the night. It often applies to someone in a position of power or responsibility, who is expected to protect and look out for the interests of those who entrusted them with this mission. It is an expression of trust and hope that the person entrusted with this responsibility will not betray that trust. The equivalent in English could be “You are trusted like a lock in which we have faith for our security.” It highlights the importance of responsibility and integrity for the person in this role.