Consider:

• I am very fond of you

Be aware that in some cultures (Britain, US for example) non-romantic expressions such as “I like you” and “I am fond of you” can be used as ways to flirt or make romantic overtures, while making rejection less embarrassing.

I really like Jean’s answer, and I also think your own translation of “I care about you holds a lot of the emotions (emotional attachment) meaning of “love”, without implying romance.

I deleted this section after comments by @MatiCicero and @ErikKowal. This is a long answer. Mati explained that ‘Te quiero’ has more a meaning of non-romantic emotional attachment (fondness) rather than admiration, appreciation or finding someone agreeable or pleasing.

I found the Oxford Thesaurus entry for fond quite disappointing, as I found many suggestions were romantic, but there are some interesting synonyms for like I think well

• of you (not as strong as love) I hold you
• in high regard (a little formal and old-fashioned)

Consider:

• I am very fond of you

Be aware that in some cultures (Britain, US for example) non-romantic expressions such as “I like you” and “I am fond of you” can be used as ways to flirt or make romantic overtures, while making rejection less embarrassing.

I really like Jean’s answer, and I also think your own translation of “I care about you holds a lot of the emotions (emotional attachment) meaning of “love”, without implying romance.

I deleted this section after comments by @MatiCicero and @ErikKowal. This is a long answer. Mati explained that ‘Te quiero’ has more a meaning of non-romantic emotional attachment (fondness) rather than admiration, appreciation or finding someone agreeable or pleasing.

I found the Oxford Thesaurus entry for fond quite disappointing, as I found many suggestions were romantic, but there are some interesting synonyms for like I think well

• of you (not as strong as love) I hold you
• in high regard (a little formal and old-fashioned)