She deliberately used Ardhamainda to make a point that she is Pallavi Raghav Rao and not their DIL anymore. It was her showing the Deshmukh family that she has changed and accepted Raghav as hers.
She was not using Ardhamainda to convey “understand?” in normal speech. Ardhamainda was a tool to convey the underlying sentiment. And so, using samazhla would not have helped at all.
Baat ki gehrai samjho re, Rado 😆