He was angry but he decided to meet her. (Make it a complex sentences.)?
The idea with this is that "but" acts to contrast the feeling of anger with the act of meeting someone. Who wants to meet with someone with whom they are angry?
In that sense, you should use word(s) that articulate the contrast, such as "although", "despite", "even though", or "in spite of", amongst other possibilities.
There has to be a reason for the contrast to be there. However these were worded, the meaning in the original sentence still articulates that:
- There was some sort of tension involving both of them beforehand that makes him hesitate to meet her at first.
- He wants to meet her for a particular reason, probably to either apologize or argue again (hopefully the former).
Perhaps the contrast is due to a previous conflict, and he wanted to meet with her to resolve that conflict.
"Despite being angry after a previous conflict, he decided to meet with her anyway in an attempt to resolve the tension between them."
"Although he was still angry with her, he resolved to meet her anyway in order to settle their previous argument in a more mature manner."
"In spite of their previous conflict resulting in an angry departure, he realized he had to make amends; as such, he wanted to meet with her to apologize."