From Longman Dictionary of Contemporary Englishbe yours/hers/his etc alonebe yours/hers/his etc aloneused to emphasize that something belongs to someone The responsibility is yours and yours alone. → alone
Examples from the Corpus
be yours/hers/his etc alone• Even when your growing brain shared my blood, your dreams were yours alone.• She had never helped with any of the bills, so he felt that the house was his alone.• The next job was his alone. 