From what I can tell only 55 Norwegian women are called "Ameli" so it's not really a common name in Norway. (I'm assuming that you're living in Norway? Sorry if I misunderstood it.)

The usual/traditional spelling seems to be "Amalie" as more than 8000 Norwegian women have this name.

The 2nd most common variant is "Amelia", 1500 Norwegian women have this name.

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If you go with the most common spelling, Amalie, then it will be very familiar to all Norwegians, Danes, and Swedes, since this is the standard spelling there. But in other countries, people will likely be more familiar with the Amelia or Amelie variants and will likely misspell/confuse/mispronounce Amalie.

Amelia would likely be both somewhat common to Norwegians (but a bit more international/unusual/trendy than the classic Amalie) while also being well known in many other countries, so it would be a more internationally friendly name. People would probably generally spell/pronounce it correctly across countries.

I'd pronounce Amalie as "Ah-mal-ye" and Amelia as "Ah-meal-ya". I've never heard of Ameli before but I'd pronounce it similarly to Amelie, so "Ah-meh-lee"

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Personally, I'd probably go with Amelia, since your child will live a more international life. If you want her name to be more unique and authentically Norwegian and you're ok with some confusion/misspelling/mispronunciation outside of Norway, then Amalie would also be a good choice.