Dude. If your concern is maturity, then it's a bit rich to be asking how to turn someone down without “hurting their feelings”.
Obviously it's going to hurt her feelings, that's unavoidable, and it's frankly immature for you to think you can escape that. The only thing you can do is be polite and kind. If she had just asked you out, it probably wouldn't more than sting to hear a no, but if she's already got 'strong feelings' then there's no avoiding hurting them.
Discuss with him. It seems to me you are both playing phone games.
Dude. If your concern is maturity, then it's a bit rich to be asking how to turn someone down without “hurting their feelings”.
Obviously it's going to hurt her feelings, that's unavoidable, and it's frankly immature for you to think you can escape that. The only thing you can do is be polite and kind. If she had just asked you out, it probably wouldn't more than sting to hear a no, but if she's already got 'strong feelings' then there's no avoiding hurting them.
That wasn’t very kind of her