# with true hearts

"with sincerity" or "sincerely" 

# in the full assurance of faith

"and with a confident faith" or "and trusting completely in Jesus"

# having our hearts sprinkled clean

"as if had he made our consciences clean with his blood" 

# sprinkled

See how you translated this in Hebrews 9:19. 

# having our bodies washed with pure water

"as if he had washed our bodies in pure water"

# our bodies washed with pure water

Possible meanings are 1) "bodies" represents peoples' entire beings, and "washed with pure water" represents Christ making a person spiritually pure or 2) this is literal and it refers to Christian baptism.