I am currently studying Japanese grammar at a beginner's level. Yes, I am familiar with Hiragana but I have not quite learnt Katakana yet. Obviously, I know Romaji and hardly much Kanji.
However, I came across the formal and informal way of using "suki" (すき). I know "desu" is required if you were to say to your boss "I like apples" but is "da" really necessary for informal? I mean, is it as polite if you went without it? Is it grammatically correct or right to go without it?
For example, what's the difference between りんごが好き ("I like apples") and and with だ on the end (sentence + grammatical particle perhaps?) 🍎