This can be stated in active form. Alternate translation: "so that you would know that your good will toward us is sincere" (See: [[rc://en/ta/man/translate/figs-activepassive]])
This refers to God's presence. God's understanding and approval of Paul's truthfulness is referred to as God being able to see them. See how you translated this in [2 Corinthians 4:2](../04/01.md). Alternate translation: "before God" or "with God as witness" (See: [[rc://en/ta/man/translate/figs-metaphor]])