Frank Pentangeli later admits that while Vito Corleone had had a long history with Roth, to include doing business with the man, liking him, and respecting him, the elder Corleone never trusted Hyman Roth.
The passage highlights a contradiction in Vito Corleone's relationship with Hyman Roth: despite having a history of business dealings and personal respect, the elder Corleone never fully trusted him.