Hindu teachers tend to tolerate Christianity, expecting it to move toward and be absorbed by Hinduism. God incarnate in Jesus Christ is, on the surface, easy for the Hindu to accept. He questions the uniqueness of the event. Vishnu, the Preserver god in Hinduism, is said to have had nine incarnations. To say God has only come in Jesus strikes Hindus as arrogance.
Divine forgiveness is incomprehensible.
Karma is immutable. Every action has an absolutely inescapable consequence. That sin can be forgiven and cancelled violates the law of Karma. Karma and reincarnation do not deter evil . If one chooses to do evil in this life, there are many more lives to work it out.