open arms,lay it on the line,in hot water

[Ju]

1) I welcome him with open arms.

• Does it mean that I really physically welcome him with my arms open?
• Is there any implication in this sentence?

2) I lay it on the line to him.

• Does it mean I talk to him frankly?
• Is it a polite expression?

3) Lay it on the line
(This is a conversation between a teacher and a disobedient student)

• In this case, does it mean the teacher will fire the student if he/she is still being disobedient?

4) My dean didn't know exactly why I had missed the classes. If he
knew the reason for my absence was to help a matchmaker. I
would have been in hot water - very hot water.

• What does it mean of I would have been in hot water - very hot water?

Thanks

[Ouisch]

Originally Posted by Ju

1) I welcome him with open arms.

• Does it mean that I really physically welcome him with my arms open?

• Not literally, but figuratively. "With open arms" means gratefully, warmly, gladly.
  
  

  Is there any implication in this sentence?

2) I lay it on the line to him.

• Does it mean I talk to him frankly?
• Is it a polite expression?

3) Lay it on the line
(This is a conversation between a teacher and a disobedient student)

• In this case, does it mean the teacher will fire the student if he/she is still being disobedient?

Yes, "lay it on the line" means you are speaking honestly and frankly. You are telling the situation exactly as it is, with no embellisment, no sparing of feelings.

Often, as in the case of the teacher and student, "lay it on the line" is used as something of an ultamatim or a warning. "I'm going to lay it on the line, Sam; your grades have been very poor this term and you've missed too many classes. If you miss one more day, I will have to fail you."

4) My dean didn't know exactly why I had missed the classes. If he
knew the reason for my absence was to help a matchmaker. I
would have been in hot water - very hot water.

• What does it mean of I would have been in hot water - very hot water?

Thanks

"In hot water" means you are in trouble. "If my dad found out I was the one who borrowed his car, I'd be in very hot water!"
In your example, the student probably would've been forgiven for missing class if he had been ill, or had a family emergency. But if the dean found out that it had been for a frivolous reason - to help a matchmaker - the student would have been in trouble.