JSFiddle - React, Tailwind, and code Playground

HTML

<div class="conditionInner">
    <div class="conditionContent">
        <div class="conditionCheck">
            <input type="checkbox" class="conditions" id="condition1" />
            <label for="condition1"></label>
        </div> <span>I accept the general conditions of likaliner and its partners</span>

    </div>
    <div class="conditionContent">
        <div class="conditionCheck">
            <input type="checkbox" class="conditions" id="condition2" />
            <label for="condition2"></label>
        </div> <span>I accept the transportation conditions of likaliner and its partners</span>

    </div>
</div>
<div class="paymentButtonWrap">
    <input type="button" class="paymentButton buttonSmall greenButton disabledButton" disabled="disabled" value="Paypal" />
    <input type="button" class="paymentButton buttonSmall greenButton disabledButton" disabled="disabled" value="Sms Send" />
</div>

CSS

.greenButton {
    background: #a1bd09;
    text-shadow: 0px 1px 1px #7f9507;
}
.buttonSmall {
    display: inline-block;
    height: 25px;
    text-transform: uppercase;
    border: none;
    outline: none;
    border-radius: 5px;
    color: #fff;
    cursor: pointer;
    font-size: 14px;
    font-weight: bold;
}
.disabledButton {
    background: #FFFFFF !important;
    border: 1px solid #DCDCDC !important;
    color: #BDBDBD !important;
    cursor: default !important;
    text-shadow: none !important;
}

JavaScript

$(document).ready(function () {

    $(".conditionCheck input[type=checkbox]").click(function () {
        var count = 0;
        $.each($(".conditionCheck input[type=checkbox]"), function () {
            if (this.checked) {
                count++;
            }
            if (count == 2) {
                $('button').removeAttr('disabled');
            }
        });
    });
});