# For the heart of this people ... I would heal them

This describes the people's spiritual condition. It means the people are stubborn and refuse to receive and understand God's truth. If they would, then they would repent and God would forgive them and welcome them back as his people. 

# the heart of this people has become dull

"these people's minds are slow to learn" or "these people can no longer learn" 

# with their ears they hardly hear

"they refuse to use their ears to listen" 

# they have shut their eyes

"they refuse to use their eyes to see" 

# understand with their heart

"understand with their minds"

# turn again

"turn back to me" or "repent"

# I would heal them

"have me receive them again"