What are traditions in engagements who usually buys the rings ect.?

Traditionally, the man buys the engagement ring and then proposes to the woman (usually by getting down on one knee, producting the ring and asking 'Will you marry me?'). (This formula varies by couple). Now, in the event of a broken engagement: If she breaks the engagement, she should return the ring to him. If he breaks it, she is entitled to keep the ring.