"其實比禮金比外母,
唔係用黎補貼嫁妝,
而係對女家一份尊重。">>Agree, not a big amount, but at least as a token of thanks to the in-laws (養育之恩) as u will leave the family and u are the ONLY child. Imagine the loss of security for your mom.
If u plan to give your mom your savings anyway, just tell her it is from yr boyfriend.好女兩頭瞞.