In the issue of 「知る」 vs 「分かる」, it might be helpful to explain that 「知る」is transitive, meaning 'understand something/someone', while 「分かる」is intransitive, meaning 'something/someone is understood'. Hence:
「知っている」 = 'I am understanding', 'you are understanding', 'he is understanding'
「分かっている」= 'I am being understood', 'you are being understood (by me)', etc.
And I suppose this is why 「分かっている」sounds pompous if your intent is really to indicate that you understand someone. Imagine saying in English, "You are being understood by me".
In the issue of 「知る」 vs
In the issue of 「知る」 vs 「分かる」, it might be helpful to explain that 「知る」is transitive, meaning 'understand something/someone', while 「分かる」is intransitive, meaning 'something/someone is understood'. Hence:
「知っている」 = 'I am understanding', 'you are understanding', 'he is understanding'
「分かっている」= 'I am being understood', 'you are being understood (by me)', etc.
And I suppose this is why 「分かっている」sounds pompous if your intent is really to indicate that you understand someone. Imagine saying in English, "You are being understood by me".