How do you say; "sweet"?
Marie Claire es una chica (muy*) linda
Marie Claire is a (very*) sweet (lovely) person
Marie Claire es una persona agradable
= Marie Claire is a nice/sweet/pleasant person
Muy = very You can add this word for emphasis if you want
As you can probably see there is often more than one way to say the same thing in Spanish as with most langiages
I hope that this helps
Tierno/a - Tender, affectionate
Agradable - Nice
Amable - Kind
Simpático/a - Nice, friendly
Dulce - Sweet (flavor), sweet, gentle, mild (person)
Genial - Sweet, cool, awesome
For more- Sweet in SpanishDict's dictionary
Please can you provide some vital/necessary context
Do you mean sweet as in
1 Sweet to eat?
2 Sweet as in nice / kind person ?
3 Sweet as in cute/attractive?
As you can see sweet can mean so many different things so can you give us a sentence to show us how you want to use it so we can help you?