Samsung is a South Korean company best known for mobile phones and other consumer electronics. Its name in Korean 삼성 (sam-seong), means “three stars”, but doesn’t refer to any three stars in particular. The Korean pronunciation is closer to /samsɒŋ/ (psalm song), but almost everyone in English-speaking countries pronounces it /sæmsʌŋ/ (Sam sung). In fact, I was prompted to write this by a video on photography in which the presenter pronounced it /sæmsʊŋ/ (closest to Sam should). Korean doesn’t have a close equivalent to English /ʊ/.
Chilsung is a very popular brand of lemonade (cider) made by the Lotte Corporation. Its name in Korean 칠성 (chil-seong) means “seven stars”, and refers to the Big Dipper. I haven’t heard enough foreigners pronounce to know how they pronounce it. Spelling both words with a u messes up foreigners’ conception of the vowel. Revised Romanisation transliterates it eo and McCune–Reischauer ŏ. u transliterates ㅜ (/u/) in both systems.
Subaru is Japanese company best known for motor vehicles. Its name also means “seven stars”, but refers to the Pleiades, or the Seven Sisters. Why are there only six stars on the Subaru logo, then? According to Wikipedia, “tradition” (?Japanese) says that one of them (?stars) is invisible. (The Pleiades actually contains nine prominent stars.) I assume this information (from English Wikipedia) is correct, because the Japanese Wikipedia page for the company is titled スバル and that for the star cluster プレアデス星団, but Google Translate gives the pronunciation for the latter as Pureadesu, which is obviously a transliteration of the English/Greek. I can’t see the word スバル on the page for the star cluster, orプレアデス on the page for the car company, but my ability to read Japanese letters is close to non-existent.
The Japanese pronunciation differs from the English in one or two ways. Definitely, the Japanese vowel in the first and third syllables is different – /ɯ/ (high back unrounded) and not /u/ (high back rounded). Possibly, Japanese is more evenly stressed, so su-ba-ru, rather than su-b-ru.
(As lower-intermediate as my Korean is, it’s way better than my Japanese, so take everything in the second half of this post with a high degree of caution. If anyone actually knows Japanese, please comment (politely).)
(Sometimes foreign companies choose a pronunciation in English which is different from that in the original language. In Korean, 현대 (hyeon-dae) is two syllables, but all the advertising in Australia pronounces it as three. And apparently at first, Australian pronounced it he-un-die, because there was a series of ads with the slogan “All day, every day, he-un-day”. LG took the easy way out.)