Girls, Why would a girl say hehe instead of haha when messaging me?

A while ago me and girl spoke often online. I was nervous and liked her. We got along well and spoke often. I asked her out and she said yes. However , she studies away from home and I study In her hometown so had to wait for her to come back. Sometimes if I really like someone I become quite nervous , and worried that maybe she wouldn’t like me or she’s too good for me etc. She would always reassure me and make sure I’m not nervous and say there’s nothing to worry about.
as months went by we both carried on with our lives. Unfortunately, she couldn’t return home because of covid and financial reasons. 6 months ago I re asked her if she would come out with me but then she said that she wasn’t looking for anything. I kinda told her I was upset about that because I really liked her and didn’t really want to date anyone else but also it felt like she was secretly just dating someone else but didn’t want to completely put me off by saying she’s dating another guy. I then didn’t talk to her for Months. She started liking all my pictures. 6-7 months went by. I still kinda liked her so I messaged her again.
this time she was more flirty, and always putting “x” even though she doesn’t put it to people. I asked if she was single she said she isn’t 🤦 With that emoji. Which kinda made me think that maybe she was hinting months ago to ask her out again by liking all my pictures. So I said “that’s a shame because I still like you and wanted to go out with you before I finish my studies” then she said she wants to come out with me and will be back soonish. So I said let me know when she is coming home. Then she said “hehe ok I will x” why did she say hehe? Is she trying to be cute? does she like me? Most girls I have dated recently I haven’t truly felt I liked loads. But I do like her and want to make effort.
Girls, Why would a girl say hehe instead of haha when messaging me?
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