To begin with/First/For a start/In the beginning,

[angliholic]

To begin with/First/For a start/In the beginning, I have no time to have a date with you.



For me, all of the underlined phrases fit in the above and mean about the same. Your advice? Thanks.

[Anglika]

The first three are indicating that this is the first of several points;
"In the beginning" indicates "initially" - this sentence is not a good use of the phrase.

The feel of the sentence is aggressive.

[angliholic]

The first three are indicating that this is the first of several points;
"In the beginning" indicates "initially" - this sentence is not a good use of the phrase.

The feel of the sentence is aggressive.

Thanks, Anglika.
Yes, the feel of the sentence is aggressive, but I didn't write it. It's just a sample.