Verified answer

Yes, in some consonant clusters one becomes mute, usually the middle one but sometimes the first. There's the consistent rule that -stn- > [sn] and -zdn- > [zn], and some individual cases for clusters that only occur in a single word; this includes serdtse [sertse] as well as solntse [sontse].

can pronounce the "D"

even pronounce all the letters in the word as it is written meaning and understanding remain, many Russian is spoken of as being written - by the way because non-native Russian language learning easier

In Russian it sounds like saying : "yeartht" meaning Heart, core, bossom etc...

* Sier-DCe

this way is better