Question: How did Michael know it was Roth behind the attempt on his life, not Frank Pentangeli?
Answer: Michael always suspected Roth, though he didn't have proof, and then believed it was Pentangeli. Michael learned that Fredo was involved in the assassination plot on his life. Fredo confessed that he was helping Roth, expecting some compensation in return, though he did not know there would be an attempt to kill Michael.
Answer: He didn't know for sure it was Ross until he went to Cuba and asked about the order on Pentangeli. Roth gave the speech about Moe Green starting Las Vegas, someone had him killed and he didn't ask. What he said to Michael told him why he wanted him killed, plus he knew Ross had ordered the hit on Pentangelli, plus he heard his brother slip up at the club earlier that he had been there before with the other guy that Michael knows is against him. That's when Michael kew his brother betrayed him - when he slipped up in the club. So Michael found out everything on New Year's Eve in Cuba.
Answer: As I recall, this scene was shortly after Mama Corleone died. Connie would still be mourning and wearing black. The other woman is not Kay's mother, but probably a random Corleone relative. Connie is grieving her mother, but also is saddened by Michael's cruelty toward Kay and at seeing Kay's emotional secret visit with her children. Michael had prevented Kay from seeing them.
raywest ★