㗎喇 is a combination of multiple Cantonese sentence final particles (SFPs):
gaa3 is a contraction of 嘅呀
ge3 is directly equivalent to Mandarin's 的
de in meaning and usage.
aa3 is used in Cantonese to soften the tone of a sentence. I don't believe Mandarin has a direct standardized equivalent to it, but some Mandarin speakers do use it in a similar manner.
laa3 is directly equivalent to Mandarin's SFP 了
le. Both of these words are actually cognate to one another, ultimately having been descended from 來 (note that this only applies to Mandarin's sentence-final 了; its post-verb 了
le actually is descended from 了
liǎo). Mandarin chose 了 to represent this word; written Cantonese isn't very standardized, so people have variously represented it using the characters 喇, 嚹, or 啦.
Given this, the Mandarin equivalent could be 的了
de le. While I noted there was no direct standard Mandarin equivalent for Cantonese's 呀, some speakers do use it. In Mandarin though, it would be attached after 了 rather than after 的; like Cantonese, it gets contracted as well, changing 了
le to 啦
la; the final result would be 的啦
de la, as @Stan mentioned in his comment.