Explanation
Used to give a reason, express cause or bring up a topic; 'because', 'since', 'it's just that'.
Formation
Verb-casual + だって、い-Adjective + だって、な-Adjective + だって、Noun + だって
Detailed explanation
The A。だって B。grammar point is used to give a reason, express cause, or introduce a topic in a casual manner. It can be translated as 'because', 'since', or 'it's just that'. A is the reason and B is the statement that follows due to the reason. It can be used with verbs, い-adjectives, な-adjectives, and nouns.
Examples
Hima datte, eiga wo mi ni ikou yo.
Since we are free, let's go watch a movie.
Samui datte, ko-to wo kite kudasai.
Because it's cold, please wear a coat.
Tsukarete iru datte, yasunda hou ga ii.
Since you're tired, it's better to rest.
Kanojo ga ryouri jouzu datte, minna kanojo no tsukutta ryouri wo tanoshimi ni shiteimasu.
Because she is good at cooking, everyone is looking forward to her dishes.
Practice
Grammar content sourced from hanabira.org.