Newark NJ Non Renewal Notice

[Summie S.]

I am trying to end a fixed term lease with tenants in Newark NJ. The original reason I gave (non agreement to full lease terms) they are now saying they didn't say, which b/c I know them I know was implied. Can I simply not give a rationale and send the non renewal notice? Or do I owe them an explanation now? Also am I within my rights as a Landlord to not renew the lease, or in Newark NJ is there a law which states I must have 'good cause' to not renew a lease.