The company was forced to 'declare bankruptcy'. [=to formally say in a legal document that it was bankrupt]
He 'declared' himself the winner. = He 'declared' that he was the winner. = He 'declared victory'.
His 'declared' [=publicly stated] aim/goal/intention is to improve the city's downtown area.
(..) I'll carry your guilty secret to my grave. I guess I'd be very unpatriotic to hate one of the great heroes of the war. I do declare I was surprised to see you turn out to be such a noble character. I can't bear to take advantage of your little girl ideas, Miss O'Hara. I'm neither noble nor heroic. (..)1939 Gone with the Wind
(..) I want to eat barbecue with you. Mind you, don't go philandering with any other girl, 'cause I'm mighty jealous. I won't, Miss O'Hara! I couldn't! I do declare, Frank Kennedy, if you don't look dashing... ...with that new set of whiskers! Oh, thank you, Miss Scarlett. Charles and Rafe asked me (..)1939 Gone with the Wind