Ces sandales sont jolies, mais celles-ci sont trop chères même avec la remise.

Because ces is the plural demonstrative adjective in French, used for both masculine and feminine nouns.

The demonstrative adjectives are:

• ce = this/that before a masculine singular noun
• cet = this/that before a masculine singular noun starting with a vowel or mute h
• cette = this/that before a feminine singular noun
• ces = these/those before any plural noun

Since sandales is plural, French uses ces.

In French, every noun has a grammatical gender. Sandale is a feminine noun, so you say:

• une sandale
• des sandales

Because it is feminine plural, any adjectives or pronouns referring to it must also match that gender and number.

Because jolies agrees with sandales, which is feminine plural.

The base adjective is joli. Its forms are:

• masculine singular: joli
• feminine singular: jolie
• masculine plural: jolis
• feminine plural: jolies

So Ces sandales sont jolies uses the feminine plural form.

For the same reason: chères agrees with celles-ci, which stands for sandales. Since sandales is feminine plural, the adjective must also be feminine plural.

Here are the forms of cher:

• masculine singular: cher
• feminine singular: chère
• masculine plural: chers
• feminine plural: chères

So celles-ci sont trop chères is grammatically matching the feminine plural noun being referred to.

Celles-ci means these ones or the latter ones here, and it is a feminine plural demonstrative pronoun.

It replaces the noun sandales so you do not have to repeat it:

• Ces sandales sont jolies, mais celles-ci...
• literally: These sandals are pretty, but these ones...

It is feminine plural because it refers to sandales.

Ces is a demonstrative adjective, so it must come directly before a noun:

• ces sandales

Celles-ci is a demonstrative pronoun, so it replaces the noun:

• celles-ci = these ones

So in the sentence:

• Ces sandales = these sandals
• celles-ci = these ones

French often uses a pronoun like this to avoid repeating the same noun.

Because French demonstrative pronouns can take -ci or -là, and these are attached with a hyphen:

• celui-ci = this one
• celui-là = that one
• celles-ci = these ones
• celles-là = those ones

Traditionally:

• -ci points to something closer
• -là points to something farther away

In modern everyday French, the distance idea is not always strict, but the hyphen is still required.

Yes, it could, depending on what you want to emphasize.

• ces sandales-ci = these sandals here
• celles-ci = these ones / these ones here

The sentence could be rephrased, but celles-ci is natural because it avoids repeating sandales. French often prefers this kind of pronoun when comparing two sets of things.

Because after the verb être, French normally uses an adjective to describe the subject.

So:

• Ces sandales sont jolies = These sandals are pretty

Here, jolies is an adjective describing sandales.

Joliment is an adverb, and adverbs do not agree with nouns the way adjectives do. It would not work here.

Trop means too or too much in the sense of excess.

So:

• trop chères = too expensive

It suggests the price is higher than acceptable, reasonable, or affordable.

Compare:

• chères = expensive
• très chères = very expensive
• trop chères = too expensive

So trop is stronger than très because it implies a problem.

Même avec means even with.

• avec = with
• même avec = even with

So même avec la remise means that the sandals are still too expensive despite the discount.

This is a common structure:

• même avec ton aide = even with your help
• même avec une réduction = even with a discount

Here, la remise means the discount.

It is similar to la réduction, and in many shopping contexts they can overlap. But there can be slight differences:

• réduction is a general word for a price reduction
• remise often refers to a discount given on the price, especially in sales or commercial contexts

So in this sentence, la remise is perfectly natural for the discount.

A careful pronunciation would be roughly:

Say sandales son jolee, may सेल-see see son tro share mem ah-vek la ruh-meez

More usefully, a few pronunciation notes:

• Ces sounds like say
• sandales ends with a clear -al sound: sahn-dahl
• sont sounds like son
• jolies sounds like zho-lee
• celles-ci sounds roughly like sel-see
• chères sounds like share
• même sounds like mem
• remise sounds like ruh-meez

There is usually a liaison in:

• sont trop → the t in sont may link to the next word in careful speech

French demonstratives are less rigid than English in everyday use. Ces can mean either these or those depending on context.

If French wants to make the distinction clearer, it can add:

• -ci for this/these
• -là for that/those

So:

• ces sandales can mean these sandals or those sandals
• celles-ci makes the meaning more specifically these ones
• celles-là would be those ones

In real conversation, context often tells you which meaning is intended.