مرحباً، أنا سيف.

Arabic is so hard to learn, but I'l keep at it.

The meaning of "keep at" in Arabic: الحفاظ على

So this is the exact translation for your sentence:

اللغة العربية صعبة التعلم، ولكن سأحافظ عليها.

But I think You meant:

اللغة العربية صعبة التعلم، ولكن سأحاول تعلمها/سأبذل جهدي لتعلمها.

I wish you good luck Saif.

أنا سيف مرحبا

Arabic is so hard to learn, but I'l keep at it.

أنا سيف، مرحبا

Arabic is so hard to learn, but I'l keep at it.

أنا سيف مرحبا

Arabic is so hard to learn, but I'l keep at it.

اول شيء مرحبا

Arabic is so hard to learn, but I'l keep at it.