"Being in love" means that you already love someone completely. "Falling in love" means you in the process of developing a love for someone.

Hallmark is a company that manufactures and sells greeting cards. If someone says you should work for Hallmark, that would usually mean you could write affectionate, emotional messages for greeting cards. However, his brother is using sarcasm, meaning that the main character is insensitive and does not care about other's feelings.

Yes, it does. But, "Hit the gas" also implies that they were in a hurry and wanted to go quickly.

Is the sentence trying to say that you do not know if it is the mother's or grandmother's name? If so, I think what you are trying to say is this: I have never heard whether it's your mother's or grandmother's name.

Water tearing through in this context sounds like there was rapid flooding water that caused destruction or damage.

This is not very clear, without seeing more of the text before it. But, to "ditch" something could mean to leave or abandon it. And "orientation" can be an introduction to something. For example, someone could have a college orientation meeting to attend when they start at a new school. If they ditch the orientation, that means they are going to skip that meeting, or leave before it is over. Does this explanation make sense in the story you are asking about?

It means the vehicles are approaching at very fast speeds, or in a reckless manner.

It is A. If you have multiple adjectives modifying one noun, then you would arrange them in order by the following: Feelings, Size, Age, Shape, Color, Origin, Material, Purpose And, as mentioned above, add "a" "before big red German". He has a big red German car.