What does "screw up" mean?

What does "freeze" mean here?

To "freeze" in this context means to "stop" or "stand still". "Freeze" is a command given when telling someone to stop moving and stand still. It can also be used to describe the state of someone who is motionless. Ex: Freeze! You're under arrest. Ex: She stood frozen and in shock of what just happened.

What's "is bound to" mean?

"Is bound to" means certain to do or have something, or obligated by law, circumstances, or duty to do or have something. Ex: It's bound to get warmer now that the winter solstice has passed. Ex: She's bound to tell the truth in a court of law.

I know the word "shit" is bad one, but why is it used here? And when can I use this word in other situation?

"Shit" here means "idea" (i.e. she wants someone to get the idea that they are only friends inside of their head). Native English speakers often use the word "shit" to simply refer to an object or idea in an assertive way. "Shit" is considered a swear word and some people are offended by it, so I recommend being careful using it. If you are unsure if you should use it, then don't use it.

Can I say "we need an innovation" instead of the existing sentence?

Yes, you could say "we need innovation," omitting "an" in "we need an innovation." "An innovation" would mean only one change rather than continual changes and processes. And it would be good to explain what one needs an innovation "in!" Ex: We need innovation in technology. Ex: Innovation is an important part of creating art.

What does "meet" mean here? Is it different from the word "meet" in "nice to meet you"?

The verb "meet" has many different meanings. It can mean to encounter, join, touch, or to greet someone. In this case, meet means to satisfy, fulfill, or achieve something. The speaker is stating that Siti had to satisfy or fulfill the airline's requirements before becoming an employee. Ex: I applied for the job because I met all the requirements. Ex: She doesn't meet the standards of our company. Ex: If I meet my sales goal, please give me a raise.