。
She was happy to have my company.
Literal
She [topic-は] I [subject-が] together being-and was-pleased for-me.
The te-form chain 一緒にいて ('being together and...') sets the cause/circumstance for the main verb 喜ぶ ('to be pleased / delighted'). Without an explicit conjunction, te-form often supplies a causal or sequential link — here 'because we were together, she was pleased.' The benefactive ~てくれる adds gratitude back at the speaker: 'she was pleased *for me / on my behalf*' — i.e., her pleasure registers as something done benefiting the speaker. This 感情動詞 + ~てくれる pattern is a subtle way to acknowledge someone else's positive feelings as a gift.