He doesn't tell her about his plans to murder Banquo and Fleance because he wants it to be a nice surprise for her. Yeah, it's crazy, but he's seriously sleep-deprived.
Lady Macbeth is not involved in the plan to kill Banquo because the decision to murder Banquo is made by Macbeth alone. Macbeth wants to keep Lady Macbeth out of this particular act of violence to protect her from its consequences and to shield her from the guilt associated with the murder of their former friend. Additionally, Macbeth wants to keep the full extent of his plans hidden from Lady Macbeth to prevent her from being implicated or becoming a target of suspicion.
Banquo probably doen't know for sure about how Macbeth is planning on killing Duncan so he can become king. Even if Banquo did know, he is a very loyal friend to Macbeth and will keep all of his suspicions to himself. Which is ironic, because Mabeth ends up hiring murderers to kill Banquo, which goes to show you that Macbeth really isn't that loyal.
Macbeth doesn't confide in Banquo because he sees Banquo as a threat to his ambition. Banquo's descendants are said to be kings according to the witches' prophecy, which poses a risk to Macbeth's position as king. Macbeth becomes increasingly paranoid and seeks to eliminate anyone who might challenge his rule.
Macbeth doesn't really have a conflict with them. Banquo suspects Macbeth of killing Duncan, but isn't saying anything. Macbeth is annoyed by the witches' prediction that his children will not succeed him (Does he have children? The way things are going between him and his wife, is it likely that he will?) but that Banquo's decendants will. He is jealous. Macbeth's murder of Banquo and attempt on Fleance's life are an attempt to prove to himself that his future is not controlled, and that he is free. He wants to know that he became king because of what he did, not some inexorable fate. When the murderers fail to kill Fleance, he says, "Then comes my fit again!". He has not proven that he is free. The witches' predictions about Banquo can come true. Maybe it is all a matter of fate after all.
because he just knows
Banquo's lines about the star's recall reflect his suspicion towards Macbeth's sudden rise to power after the witches' prophecy. Earlier, Banquo had warned Macbeth about the deceptive nature of the witches and their prophecies, suggesting that they might lead to harm or destruction. This sets up Banquo as a foil to Macbeth, highlighting his moral integrity and skepticism compared to Macbeth's ambitious and deceitful nature.
If he did, it is not shown in the play. As far as we know, he only had the one chance encounter with them.
I would say, Banquo had will. His will out weighed any temptations he had towards his goals. Though, just as ambitious as Macbeth, Banquo held back, happy to sit in the back seat as Macbeth explored the front row. This, truthfully would have been better in the long run (you know what they say about the tortoise and the hare) if it wasn't for Macbeth's greed and paranoia.
The general opinion is that his sons Malcolm and Donalbain had hired his grooms to kill their father. This was supposedly proven because they took off after the murder was discovered, a sign of guilt. This is explained by Macduff in Act II Scene 4.
Lady Macbeth wasn't in on her husband's plans to kill Banquo. When she asked what his plans 'of dreadful note' [Act 3 Scene 2 Line 44] were, he didn't want her to know the specifics. But most likely yes, she would have wanted Macbeth to kill Banquo. Earlier in their conversation, she commented that Banquo and his son Fleance were mortal [and therefore killable?].
Macbeth wants Banquo dead because Banquo witnessed what the three witches said. The three witches stated that Macbeth would one day become king. Now that Macbeth has become king, and done so by taking the life of the previous King Duncan, he fears that Banquo will spread the word that Macbeth was the one to commit the murder.
Macbeth sees Banquo's descendants because the witches predicted that Banquo's descendants would inherit the throne. This prophecy threatens Macbeth's reign and pushes him further into paranoia and violence, leading him to order the murder of Banquo and attempt to also eliminate Banquo's son, Fleance.
i think Macbeth wanted to be king. he couldn't though because king Duncan was. So Macbeth killed him. Then Banqou was suppose to be next to be kind, i believe. So he hired the revengers or avengers to murder him. Next was fleance. i don't know what happened to him.