Welcome to WordReference Forum chiquilla11. Please read the stickies at the top of the forum (the closed links that you can still read) to get some suggestions on how to post, especially in giving context when asking for a question. It really is there to help those who want to help you be more accurate in giving you help.
mjscott is right, but we'll go easy on a new member. Bust into usually means break into, as a burglar would break into a house. There is also a similar phrase, burst into which usually refers to starting to sing. More context would be helpful.
"Bust" is a non-standard variant of "burst", meaning "break". It is common in conversation, but it is considered by many to be an uneducated thing to say, and it should never be used in formal writing.