As GET has so many meanings, it is hard for me to distinct between them and understand the nuances. Are these sentences all correct? Would you understand the same thing by them?
I will settle you in.
I will get you settled in.
Let's get you settled in!
Is the first one acceptable?
I've never heard the first one used, and as it comes uncomfortably close to the slightly outdated idiomatic phrase "settle [one's] hash," it could be easily misinterpreted.
The second and third variants are mostly equivalent. The second variant implies that the speaker will perform all the necessary activities to get the listener settled in, whereas the use of "let's" in the third variant (referring to the speaker and the listener) implies a joint activity. The best variant to use depends on the specifics of the situation. In a scenario such as a manager welcoming a new employee on their first day, for example, getting settled in might include showing the new employee where the mailroom and restrooms are, introducing them to the rest of the team, and so forth. This involves the participation of both the manager and the new employee, so "lets's" would probably be a better choice.
I'll (just) make sure you're settled in sounds less self-promoting than your second alternative (the I'll helps). Your third alternative sounds fine (if rather 'jollying' - not quite patronising).
Rather than just think 'get has many meanings', I'd say it's more accurate to consider that 'get is often used as a function- rather than a lexical word'. It is used as an auxiliary (eg get married) and as a component of fixed expressions (get ready, get real...)
