# who sell the word of God

"who sell God's message" 

# purity of motives

"pure motives"

# we speak in Christ

"we speak as people who are joined to Christ" or "we speak with the authority of Christ"

# as we are sent from God

"as people whom God has sent" 

# in the sight of God

This represents the presence of God. Paul and his coworkers preach the gospel with the awareness that God is watching them. Alternate translation: "speaking in the presence of God"