"You must understand me."

Translation: Kamu harus memahami saya.

[donny309620]

Is acceptable to say "mengertikan" in place of "memahami"?

[Rick392366]

Is acceptable to say "mengertikan" in place of "memahami"?

memahami = mengerti <== synonyms. ('to undesrtand')

'mengertikan' = to make (someone else) understand.

The sentence would have a different meaning:
'Kamu harus memahami saya.' = 'You must understand me.'
'Kamu harus mengerti saya.' = 'You must understand me.'
'Kamu harus mengertikan saya.' = 'You must make me understand.'

KBBI definition:
https://kbbi.web.id/erti

mengertikan/meng·er·ti·kan/ v
menjadikan (membuat) mengerti:
memang sukar ~ orang setolol dia;