I had some questions about the verb 'to be'. I know you have the copula 「だ」 and 「いる」and「ある」. However, the copula does not have all the conjugations, so how would you express something like 'can be' or 'make be'(like in: 'I made him happy'). And use expressions like 「なければならない」would you form something like 「じゃなければならない」? Or the expression 「～たい」(Like in: 'I want to be happy'). I don't really know. I suggest maybe using 「である」. But I know that's really like literary language. Also how would you say all this with i-adjectives?
Well, Thank you, in advance.